1
|
Fang X, Hilton B, Clarkson K, Rogers RC, Schroer R, Childers A, Patterson WG, Davis JM, Everman DB, DuPont BR. Large Chromosome 2p Duplication-Associated Mechanisms and Clinical Presentations. Cytogenet Genome Res 2023; 163:14-23. [PMID: 37497920 DOI: 10.1159/000533218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023] Open
Abstract
Chromosome 2p (chr2p) duplication, also known as trisomy 2p, is a rare chromosome abnormality associated with developmental delay, intellectual disability, behavioral problems, and distinctive facial features. Most of the reported cases involving trisomy 2p include additional copy number variants (CNVs) in other regions of the genome and are usually small in size. Little is known about the clinical outcomes of large duplications of chr2p as the sole cytogenetic abnormality. In this study, 193 samples at the Greenwood Genetic Center (GGC) with CNVs involving chr2p were evaluated, out of which 86 had chr2p duplications. Among them, 8 patients were identified with large chr2p duplications ranging in size from 9.3 Mb to 89 Mb, and no deletions or duplications involving other chromosomes were identified in those patients. These duplications were associated with inverted duplication, tandem duplication, and duplication as the result of translocation, with no additional CNVs identified by microarray analysis. Confirmation by conventional cytogenetics was performed in 7 of the 8 patients, and the translocations were confirmed by fluorescence in situ hybridization. Interestingly, 1 patient was found to have mosaic complete trisomy 2p as the result of an unbalanced de novo (X;2) chromosomal translocation. X-inactivation was skewed toward the derivative X chromosome, yet it did not appear to extend into the chromosome 2 material. Various shared clinical manifestations were observed in the individuals in this study, including developmental delay, hemifacial hypoplasia, cleft palate, and short stature, and they also have distinct features such as hypotonia, cerebellar hypogenesis, and corpus callosum agenesis, which might result from a gene dosage effect of the duplication. In conclusion, single-event large chr2p duplications can result from different mechanisms, including inverted or tandem duplications within chromosome 2, or translocations involving chromosome 2 and other chromosomes. Partial or complete trisomy 2p is commonly associated with developmental delay, and additional clinical features may be related to gene dosage effects.
Collapse
Affiliation(s)
- Xiaolan Fang
- Greenwood Genetic Center, Greenwood, South Carolina, USA
| | | | - Katie Clarkson
- Greenwood Genetic Center, Greenwood, South Carolina, USA
| | | | | | - Anna Childers
- Greenwood Genetic Center, Greenwood, South Carolina, USA
| | | | | | | | | |
Collapse
|
2
|
Dutrillaux B, Dutrillaux AM. Why Are X Autosome Rearrangements so Frequent in Beetles? A Study of 50 Cases. Genes (Basel) 2023; 14:150. [PMID: 36672891 PMCID: PMC9859168 DOI: 10.3390/genes14010150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/14/2022] [Accepted: 12/27/2022] [Indexed: 01/09/2023] Open
Abstract
Amongst the 460 karyotypes of Polyphagan Coleoptera that we studied, 50 (10.8%) were carriers of an X autosome rearrangement. In addition to mitotic metaphase analysis, the correct diagnosis was performed on meiotic cells, principally at the pachytene stage. The percentages of these inter-chromosomal rearrangements, principally fusions, varied in relation to the total diploid number of chromosomes: high (51%) below 19, null at 19, low (2.7%) at 20 (the ancestral and modal number), and slightly increasing from 7.1% to 16.7% from 22 to above 30. The involvement of the X in chromosome fusions appears to be more than seven-fold higher than expected for the average of the autosomes. Examples of karyotypes with X autosome rearrangements are shown, including insertion of the whole X in the autosome (ins(A;X)), which has never been reported before in animals. End-to-end fusions (Robertsonian translocations, terminal rearrangements, and pseudo-dicentrics) are the most frequent types of X autosome rearrangements. As in the 34 species with a 19,X formula, there was no trace of the Y chromosome in the 50 karyotypes with an X autosome rearrangement, which demonstrates the dispensability of this chromosome. In most instances, C-banded heterochromatin was present at the X autosome junction, which suggests that it insulates the gonosome from the autosome portions, whose genes are subjected to different levels of expression. Finally, it is proposed that the very preferential involvement of the X in inter-chromosome rearrangements is explained by: (1) the frequent acrocentric morphology of the X, thus the terminal position of constitutive heterochromatin, which can insulate the attached gonosomal and autosomal components; (2) the dispensability of the Y chromosome, which considerably minimizes the deleterious consequences of the heterozygous status in male meiosis, (3) following the rapid loss of the useless Y chromosome, the correct segregation of the X autosome-autosome trivalent, which ipso facto is ensured by a chiasma in its autosomal portion.
Collapse
Affiliation(s)
- Bernard Dutrillaux
- Institut de Systématique, Évolution, Biodiversité, ISYEB-UMR 7205–CNRS, MNHN, EPHE, Sorbonne Université, 57 rue Cuvier CP50 F, 75005 Paris, France
| | | |
Collapse
|
3
|
Oliveira da Silva W, Rosa CC, Ferguson-Smith MA, O'Brien PCM, Saldanha J, Rossi RV, Pieczarka JC, Nagamachi CY. The emergence of a new sex-system (XX/XY 1Y 2) suggests a species complex in the "monotypic" rodent Oecomys auyantepui (Rodentia, Sigmodontinae). Sci Rep 2022; 12:8690. [PMID: 35610291 PMCID: PMC9130129 DOI: 10.1038/s41598-022-12706-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/11/2022] [Indexed: 11/15/2022] Open
Abstract
X-autosome translocation (XY1Y2) has been reported in distinct groups of vertebrates suggesting that the rise of a multiple sex system within a species may act as a reproductive barrier and lead to speciation. The viability of this system has been linked with repetitive sequences located between sex and autosomal portions of the translocation. Herein, we investigate Oecomys auyantepui, using chromosome banding and Fluorescence In Situ Hybridization with telomeric and Hylaeamys megacephalus whole-chromosome probes, and phylogenetic reconstruction using mtDNA and nuDNA sequences. We describe an amended karyotype for O. auyantepui (2n = 64♀65♂/FNa = 84) and report for the first time a multiple sex system (XX/XY1Y2) in Oryzomyini rodents. Molecular data recovered O. auyantepui as a monophyletic taxon with high support and cytogenetic data indicate that O. auyantepui may exist in two lineages recognized by distinct sex systems. The Neo-X exhibits repetitive sequences located between sex and autosomal portions, which would act as a boundary between these two segments. The G-banding comparisons of the Neo-X chromosomes of other Sigmodontinae taxa revealed a similar banding pattern, suggesting that the autosomal segment in the Neo-X can be shared among the Sigmodontinae lineages with a XY1Y2 sex system.
Collapse
Affiliation(s)
- Willam Oliveira da Silva
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, Pará, Brazil
| | - Celina Coelho Rosa
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, Pará, Brazil
| | - Malcolm Andrew Ferguson-Smith
- Department of Veterinary Medicine, Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, UK
| | - Patricia Caroline Mary O'Brien
- Department of Veterinary Medicine, Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, UK
| | - Juliane Saldanha
- Departamento de Biologia e Zoologia, Instituto de Biociências, Universidade Federal do Mato Grosso (UFMT), Cuiabá, Mato Grosso, Brazil
| | - Rogério Vieira Rossi
- Departamento de Biologia e Zoologia, Instituto de Biociências, Universidade Federal do Mato Grosso (UFMT), Cuiabá, Mato Grosso, Brazil
| | - Julio Cesar Pieczarka
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, Pará, Brazil
| | - Cleusa Yoshiko Nagamachi
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, Pará, Brazil.
| |
Collapse
|
4
|
Saunders PA, Veyrunes F. Unusual Mammalian Sex Determination Systems: A Cabinet of Curiosities. Genes (Basel) 2021; 12:1770. [PMID: 34828376 PMCID: PMC8617835 DOI: 10.3390/genes12111770] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/29/2021] [Accepted: 11/05/2021] [Indexed: 11/21/2022] Open
Abstract
Therian mammals have among the oldest and most conserved sex-determining systems known to date. Any deviation from the standard XX/XY mammalian sex chromosome constitution usually leads to sterility or poor fertility, due to the high differentiation and specialization of the X and Y chromosomes. Nevertheless, a handful of rodents harbor so-called unusual sex-determining systems. While in some species, fertile XY females are found, some others have completely lost their Y chromosome. These atypical species have fascinated researchers for over 60 years, and constitute unique natural models for the study of fundamental processes involved in sex determination in mammals and vertebrates. In this article, we review current knowledge of these species, discuss their similarities and differences, and attempt to expose how the study of their exceptional sex-determining systems can further our understanding of general processes involved in sex chromosome and sex determination evolution.
Collapse
Affiliation(s)
- Paul A. Saunders
- Institut des Sciences de l’Evolution de Montpellier, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), 34090 Montpellier, France;
- School of Natural Sciences, University of Tasmania, Sandy Bay, TAS 7000, Australia
| | - Frédéric Veyrunes
- Institut des Sciences de l’Evolution de Montpellier, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), 34090 Montpellier, France;
| |
Collapse
|
5
|
Lisachov AP, Tishakova KV, Romanenko SA, Molodtseva AS, Prokopov DY, Pereira JC, Ferguson-Smith MA, Borodin PM, Trifonov VA. Whole-chromosome fusions in the karyotype evolution of Sceloporus (Iguania, Reptilia) are more frequent in sex chromosomes than autosomes. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200099. [PMID: 34304596 DOI: 10.1098/rstb.2020.0099] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Whole-chromosome fusions play a major role in the karyotypic evolution of reptiles. It has been suggested that certain chromosomes tend to fuse with sex chromosomes more frequently than others. However, the comparative genomic synteny data are too scarce to draw strong conclusions. We obtained and sequenced chromosome-specific DNA pools of Sceloporus malachiticus, an iguanian species which has experienced many chromosome fusions. We found that four of seven lineage-specific fusions involved sex chromosomes, and that certain syntenic blocks which constitute the sex chromosomes, such as the homologues of the Anolis carolinensis chromosomes 11 and 16, are repeatedly involved in sex chromosome formation in different squamate species. To test the hypothesis that the karyotypic shift could be associated with changes in recombination patterns, we performed a synaptonemal complex analysis in this species and in Sceloporus variabilis (2n = 34). It revealed that the sex chromosomes in S. malachiticus had two distal pseudoautosomal regions and a medial differentiated region. We found that multiple fusions little affected the recombination rate in S. malachiticus. Our data confirm more frequent involvement of certain chromosomes in sex chromosome formation, but do not reveal a connection between the gonosome-autosome fusions and the evolution of recombination rate. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
Collapse
Affiliation(s)
- Artem P Lisachov
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen 625003, Russia.,Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia
| | - Katerina V Tishakova
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Svetlana A Romanenko
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Anna S Molodtseva
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia
| | - Dmitry Yu Prokopov
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia
| | - Jorge C Pereira
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Malcolm A Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Pavel M Borodin
- Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Vladimir A Trifonov
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| |
Collapse
|
6
|
Volleth M, Khan FAA, Müller S, Baker RJ, Arenas-Viveros D, Stevens RD, Trifonov V, Liehr T, Heller KG, Sotero-Caio CG. Cytogenetic Investigations in Bornean Rhinolophoidea Revealed Cryptic Diversity in Rhinolophus sedulus Entailing Classification of Peninsular Malaysia Specimens as a New Species. ACTA CHIROPTEROLOGICA 2021. [DOI: 10.3161/15081109acc2021.23.1.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Marianne Volleth
- Department of Human Genetics, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany
| | - Faisal A. A. Khan
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Stefan Müller
- Institute of Human Genetics, Munich University Hospital, Ludwig-Maximilians University, Goethestr. 29, 80336 Munich, Germany
| | - Robert J. Baker
- Department of Biological Sciences, Texas Tech University, 2901 Main St., 79409-3131, Lubbock, Texas, USA
| | - Daniela Arenas-Viveros
- Department of Biological Sciences, Texas Tech University, 2901 Main St., 79409-3131, Lubbock, Texas, USA
| | - Richard D. Stevens
- Department of Natural Resources Management and Natural Sciences Research Laboratory of the Museum of Texas Tech University, Lubbock, TX 79409-3131, USA
| | - Vladimir Trifonov
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Lavrentiev Avenue 8/2, 630090, Novosibirsk, Russia
| | - Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Am Klinikum 1, 07747 Jena, Germany
| | | | - Cibele G. Sotero-Caio
- Department of Biological Sciences, Texas Tech University, 2901 Main St., 79409-3131, Lubbock, Texas, USA
| |
Collapse
|
7
|
Vozdova M, Kubickova S, Martínková N, Galindo DJ, Bernegossi AM, Cernohorska H, Kadlcikova D, Musilová P, Duarte JM, Rubes J. Satellite DNA in Neotropical Deer Species. Genes (Basel) 2021; 12:genes12010123. [PMID: 33478071 PMCID: PMC7835801 DOI: 10.3390/genes12010123] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 01/04/2023] Open
Abstract
The taxonomy and phylogenetics of Neotropical deer have been mostly based on morphological criteria and needs a critical revision on the basis of new molecular and cytogenetic markers. In this study, we used the variation in the sequence, copy number, and chromosome localization of satellite I-IV DNA to evaluate evolutionary relationships among eight Neotropical deer species. Using FISH with satI-IV probes derived from Mazama gouazoubira, we proved the presence of satellite DNA blocks in peri/centromeric regions of all analyzed deer. Satellite DNA was also detected in the interstitial chromosome regions of species of the genus Mazama with highly reduced chromosome numbers. In contrast to Blastocerus dichotomus, Ozotoceros bezoarticus, and Odocoileus virginianus, Mazama species showed high abundance of satIV DNA by FISH. The phylogenetic analysis of the satellite DNA showed close relationships between O. bezoarticus and B. dichotomus. Furthermore, the Neotropical and Nearctic populations of O. virginianus formed a single clade. However, the satellite DNA phylogeny did not allow resolving the relationships within the genus Mazama. The high abundance of the satellite DNA in centromeres probably contributes to the formation of chromosomal rearrangements, thus leading to a fast and ongoing speciation in this genus, which has not yet been reflected in the satellite DNA sequence diversification.
Collapse
Affiliation(s)
- Miluse Vozdova
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
- Correspondence: ; Tel.: +4205-3333-1422
| | - Svatava Kubickova
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
| | - Natália Martínková
- Institute of Vertebrate Biology, Czech Academy of Sciences, Kvetna 8, 603 65 Brno, Czech Republic;
| | - David Javier Galindo
- Deer Research and Conservation Center (NUPECCE), School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), 14884-900 Jaboticabal, Brazil; (D.J.G.); (A.M.B.); (J.M.D.)
| | - Agda Maria Bernegossi
- Deer Research and Conservation Center (NUPECCE), School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), 14884-900 Jaboticabal, Brazil; (D.J.G.); (A.M.B.); (J.M.D.)
| | - Halina Cernohorska
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
| | - Dita Kadlcikova
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
| | - Petra Musilová
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
| | - Jose Mauricio Duarte
- Deer Research and Conservation Center (NUPECCE), School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), 14884-900 Jaboticabal, Brazil; (D.J.G.); (A.M.B.); (J.M.D.)
| | - Jiri Rubes
- Department of Genetics and Reproductive Biotechnologies, Central European Institute of Technology—Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic; (S.K.); (H.C.); (D.K.); (P.M.); (J.R.)
| |
Collapse
|
8
|
Chromosomal Analysis in Crotophaga ani (Aves, Cuculiformes) Reveals Extensive Genomic Reorganization and an Unusual Z-Autosome Robertsonian Translocation. Cells 2020; 10:cells10010004. [PMID: 33375072 PMCID: PMC7822047 DOI: 10.3390/cells10010004] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/11/2020] [Accepted: 12/18/2020] [Indexed: 01/14/2023] Open
Abstract
Although cytogenetics studies in cuckoos (Aves, Cuculiformes) have demonstrated an interesting karyotype variation, such as variations in the chromosome morphology and diploid number, their chromosome organization and evolution, and relation with other birds are poorly understood. Hence, we combined conventional and molecular cytogenetic approaches to investigate chromosome homologies between chicken and the smooth-billed ani (Crotophaga ani). Our results demonstrate extensive chromosome reorganization in C. ani, with interchromosomal rearrangements involving macro and microchromosomes. Intrachromosomal rearrangements were observed in some macrochromosomes, including the Z chromosome. The most evolutionary notable finding was a Robertsonian translocation between the microchromosome 17 and the Z chromosome, a rare event in birds. Additionally, the simple short repeats (SSRs) tested here were preferentially accumulated in the microchromosomes and in the Z and W chromosomes, showing no relationship with the constitutive heterochromatin regions, except in the W chromosome. Taken together, our results suggest that the avian sex chromosome is more complex than previously postulated and revealed the role of microchromosomes in the avian sex chromosome evolution, especially cuckoos.
Collapse
|
9
|
Gil-Fernández A, Saunders PA, Martín-Ruiz M, Ribagorda M, López-Jiménez P, Jeffries DL, Parra MT, Viera A, Rufas JS, Perrin N, Veyrunes F, Page J. Meiosis reveals the early steps in the evolution of a neo-XY sex chromosome pair in the African pygmy mouse Mus minutoides. PLoS Genet 2020; 16:e1008959. [PMID: 33180767 PMCID: PMC7685469 DOI: 10.1371/journal.pgen.1008959] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/24/2020] [Accepted: 10/06/2020] [Indexed: 01/30/2023] Open
Abstract
Sex chromosomes of eutherian mammals are highly different in size and gene content, and share only a small region of homology (pseudoautosomal region, PAR). They are thought to have evolved through an addition-attrition cycle involving the addition of autosomal segments to sex chromosomes and their subsequent differentiation. The events that drive this process are difficult to investigate because sex chromosomes in almost all mammals are at a very advanced stage of differentiation. Here, we have taken advantage of a recent translocation of an autosome to both sex chromosomes in the African pygmy mouse Mus minutoides, which has restored a large segment of homology (neo-PAR). By studying meiotic sex chromosome behavior and identifying fully sex-linked genetic markers in the neo-PAR, we demonstrate that this region shows unequivocal signs of early sex-differentiation. First, synapsis and resolution of DNA damage intermediates are delayed in the neo-PAR during meiosis. Second, recombination is suppressed or largely reduced in a large portion of the neo-PAR. However, the inactivation process that characterizes sex chromosomes during meiosis does not extend to this region. Finally, the sex chromosomes show a dual mechanism of association at metaphase-I that involves the formation of a chiasma in the neo-PAR and the preservation of an ancestral achiasmate mode of association in the non-homologous segments. We show that the study of meiosis is crucial to apprehend the onset of sex chromosome differentiation, as it introduces structural and functional constrains to sex chromosome evolution. Synapsis and DNA repair dynamics are the first processes affected in the incipient differentiation of X and Y chromosomes, and they may be involved in accelerating their evolution. This provides one of the very first reports of early steps in neo-sex chromosome differentiation in mammals, and for the first time a cellular framework for the addition-attrition model of sex chromosome evolution. Sex chromosomes seem to evolve and differentiate at different rates in different taxa. The reasons for this variability are still debated. It is well established that recombination suppression around the sex-determining region triggers differentiation, and several studies have investigated this process from a genetic point of view. However, the cellular context in which recombination arrest occurs has received little attention so far. In this report, we show that meiosis, the cellular division in which pairing and recombination between chromosomes takes place, can affect the incipient differentiation of X and Y chromosomes. Combining cytogenetic and genomic approaches, we found that in the African pygmy mouse Mus minutoides, which has recently undergone sex chromosome-autosome fusions, synapsis and DNA repair dynamics are disturbed along the newly added region of the sex chromosomes. We argue that these alterations are a by-product of the fusion itself, and cause recombination suppression across a large region of the neo-sex chromosome pair. Therefore, we propose that the meiotic context in which sex or neo-sex chromosomes arise is crucial to understand the very early stages of their differentiation, as it could promote or hinder recombination suppression, and therefore impact the rate at which these chromosomes differentiate.
Collapse
Affiliation(s)
- Ana Gil-Fernández
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paul A. Saunders
- Institut des Sciences de l'Evolution, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), Montpellier, France
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Marta Martín-Ruiz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Ribagorda
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pablo López-Jiménez
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel L. Jeffries
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - María Teresa Parra
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Alberto Viera
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Julio S. Rufas
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Frederic Veyrunes
- Institut des Sciences de l'Evolution, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), Montpellier, France
| | - Jesús Page
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
| |
Collapse
|
10
|
Kretschmer R, Furo IDO, Gomes AJB, Kiazim LG, Gunski RJ, Garnero ADV, Pereira JC, Ferguson-Smith MA, de Oliveira EHC, Griffin DK, de Freitas TRO, O’Connor RE. A Comprehensive Cytogenetic Analysis of Several Members of the Family Columbidae (Aves, Columbiformes). Genes (Basel) 2020; 11:genes11060632. [PMID: 32521831 PMCID: PMC7349364 DOI: 10.3390/genes11060632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 11/18/2022] Open
Abstract
The Columbidae species (Aves, Columbiformes) show considerable variation in their diploid numbers (2n = 68-86), but there is limited understanding of the events that shaped the extant karyotypes. Hence, we performed whole chromosome painting (wcp) for paints GGA1-10 and bacterial artificial chromosome (BAC) probes for chromosomes GGA11-28 for Columbina passerina, Columbina talpacoti, Patagioenas cayennensis, Geotrygon violacea and Geotrygon montana. Streptopelia decaocto was only investigated with paints because BACs for GGA10-28 had been previously analyzed. We also performed phylogenetic analyses in order to trace the evolutionary history of this family in light of chromosomal changes using our wcp data with chicken probes and from Zenaida auriculata, Columbina picui, Columba livia and Leptotila verreauxi, previously published. G-banding was performed on all these species. Comparative chromosome paint and G-banding results suggested that at least one interchromosomal and many intrachromosomal rearrangements had occurred in the diversification of Columbidae species. On the other hand, a high degree of conservation of microchromosome organization was observed in these species. Our cladistic analysis, considering all the chromosome rearrangements detected, provided strong support for L. verreauxi and P. cayennensis, G. montana and G. violacea, C. passerina and C. talpacoti having sister taxa relationships, as well as for all Columbidae species analyzed herein. Additionally, the chromosome characters were mapped in a consensus phylogenetic topology previously proposed, revealing a pericentric inversion in the chromosome homologous to GGA4 in a chromosomal signature unique to small New World ground doves.
Collapse
Affiliation(s)
- Rafael Kretschmer
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (L.G.K.); (D.K.G.);
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre 91509-900, Brazil;
- Correspondence:
| | - Ivanete de Oliveira Furo
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, Brazil;
- Laboratório de Cultura de Tecidos e Citogenética, SAMAM, Instituto Evandro Chagas, Ananindeua 67030-000, Brazil;
| | | | - Lucas G. Kiazim
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (L.G.K.); (D.K.G.);
| | - Ricardo José Gunski
- Laboratório de Diversidade Genética Animal, Universidade Federal do Pampa, São Gabriel 97300-162, Brazil; (R.J.G.); (A.d.V.G.)
| | - Analía del Valle Garnero
- Laboratório de Diversidade Genética Animal, Universidade Federal do Pampa, São Gabriel 97300-162, Brazil; (R.J.G.); (A.d.V.G.)
| | - Jorge C. Pereira
- Animal and Veterinary Research Centre (CECAV), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal;
| | - Malcolm A. Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, University of Cambridge Department of Veterinary Medicine, Cambridge CB3 0ES, UK;
| | - Edivaldo Herculano Corrêa de Oliveira
- Laboratório de Cultura de Tecidos e Citogenética, SAMAM, Instituto Evandro Chagas, Ananindeua 67030-000, Brazil;
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém 66075-110, Brazil
| | - Darren K. Griffin
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (L.G.K.); (D.K.G.);
| | | | - Rebecca E. O’Connor
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (L.G.K.); (D.K.G.);
| |
Collapse
|
11
|
Paço A, Freitas R, Vieira-da-Silva A. Conversion of DNA Sequences: From a Transposable Element to a Tandem Repeat or to a Gene. Genes (Basel) 2019; 10:E1014. [PMID: 31817529 PMCID: PMC6947457 DOI: 10.3390/genes10121014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 11/18/2019] [Accepted: 11/29/2019] [Indexed: 01/24/2023] Open
Abstract
Eukaryotic genomes are rich in repetitive DNA sequences grouped in two classes regarding their genomic organization: tandem repeats and dispersed repeats. In tandem repeats, copies of a short DNA sequence are positioned one after another within the genome, while in dispersed repeats, these copies are randomly distributed. In this review we provide evidence that both tandem and dispersed repeats can have a similar organization, which leads us to suggest an update to their classification based on the sequence features, concretely regarding the presence or absence of retrotransposons/transposon specific domains. In addition, we analyze several studies that show that a repetitive element can be remodeled into repetitive non-coding or coding sequences, suggesting (1) an evolutionary relationship among DNA sequences, and (2) that the evolution of the genomes involved frequent repetitive sequence reshuffling, a process that we have designated as a "DNA remodeling mechanism". The alternative classification of the repetitive DNA sequences here proposed will provide a novel theoretical framework that recognizes the importance of DNA remodeling for the evolution and plasticity of eukaryotic genomes.
Collapse
Affiliation(s)
- Ana Paço
- MED-Mediterranean Institute for Agriculture, Environment and Development, University of Évora, 7002–554 Évora, Portugal;
| | - Renata Freitas
- IBMC-Institute for Molecular and Cell Biology, University of Porto, R. Campo Alegre 823, 4150–180 Porto, Portugal;
- I3S-Institute for Innovation and Health Research, University of Porto, Rua Alfredo Allen, 208, 4200–135 Porto, Portugal
- ICBAS-Institute of Biomedical Sciences Abel Salazar, University of Porto, 4050-313 Porto, Portugal
| | - Ana Vieira-da-Silva
- MED-Mediterranean Institute for Agriculture, Environment and Development, University of Évora, 7002–554 Évora, Portugal;
| |
Collapse
|
12
|
Baudat F, de Massy B, Veyrunes F. Sex chromosome quadrivalents in oocytes of the African pygmy mouse Mus minutoides that harbors non-conventional sex chromosomes. Chromosoma 2019; 128:397-411. [PMID: 30919035 DOI: 10.1007/s00412-019-00699-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 12/13/2022]
Abstract
Eutherian mammals have an extremely conserved sex-determining system controlled by highly differentiated sex chromosomes. Females are XX and males XY, and any deviation generally leads to infertility, mainly due to meiosis disruption. The African pygmy mouse (Mus minutoides) presents an atypical sex determination system with three sex chromosomes: the classical X and Y chromosomes and a feminizing X chromosome variant, called X*. Thus, three types of females coexist (XX, XX*, and X*Y) that all show normal fertility. Moreover, the three chromosomes (X and Y on one side and X* on the other side) are fused to different autosomes, which results in the inclusion of the sex chromosomes in a quadrivalent in XX* and X*Y females at meiotic prophase. Here, we characterized the configurations adopted by these sex chromosome quadrivalents during meiotic prophase. The XX* quadrivalent displayed a closed structure in which all homologous chromosome arms were fully synapsed and with sufficient crossovers to ensure the reductional segregation of all chromosomes at the first meiotic division. Conversely, the X*Y quadrivalents adopted either a closed configuration with non-homologous synapsis of the X* and Y chromosomes or an open chain configuration in which X* and Y remained asynapsed and possibly transcriptionally silenced. Moreover, the number of crossovers was insufficient to ensure chromosome segregation in a significant fraction of nuclei. Together, these findings raise questions about the mechanisms allowing X*Y females to have a level of fertility as good as that of XX and XX* females, if not higher.
Collapse
Affiliation(s)
- Frédéric Baudat
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France.
| | - Bernard de Massy
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
| | - Frédéric Veyrunes
- Institut des Sciences de l'Evolution, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), Montpellier, France.
| |
Collapse
|
13
|
Oliveira da Silva W, Rodrigues da Costa MJ, Pieczarka JC, Rissino J, Pereira JC, Ferguson-Smith MA, Nagamachi CY. Identification of two independent X-autosome translocations in closely related mammalian (Proechimys) species. Sci Rep 2019; 9:4047. [PMID: 30858413 PMCID: PMC6411977 DOI: 10.1038/s41598-019-40593-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 02/19/2019] [Indexed: 11/13/2022] Open
Abstract
Multiple sex chromosome systems have been described for several mammalian orders, with different species from the same genus sharing the same system (e.g., X1X2Y or XY1Y2). This is important because the translocated autosome may be influenced by the evolution of the recipient sex chromosome, and this may be related to speciation. It is often thought that the translocation of an autosome to a sex chromosome may share a common origin among phylogenetically related species. However, the neo-X chromosomes of Proechimys goeldii (2n = 24♀, 25♂/NFa = 42) and Proechimys gr. goeldii (2n = 16♀, 17♂/NFa = 14) have distinct sizes and morphologies that have made it difficult to determine whether they have the same or different origins. This study investigates the origins of the XY1Y2 sex chromosome determination system in P. goeldii (PGO) and P. gr. goeldii (PGG) and elucidates the chromosomal rearrangements in this low-diploid-number group of Proechimys species. Toward this end, we produced whole-chromosome probes for P. roberti (PRO; 2n = 30♂/NFa = 54) and P. goeldii (2n = 25♂/NFa = 42) and used them in comparative chromosomal mapping. Our analysis reveals that multiple translocations and inversions are responsible for the karyotype diversity of these species, with only three whole-chromosomes conserved between PRO and PGO and eight between PGO and PGG. Our data indicate that multiple sex chromosome systems have originated twice in Proechimys. As small populations are prone to the fixation of chromosomal rearrangements, we speculate that biological features of Rodentia contribute to this fixation. We also highlight the potential of these rodents as a model for studying sex chromosome evolution.
Collapse
Affiliation(s)
- Willam Oliveira da Silva
- Centro de Estudos Avançados da Biodiversidade, Laboratório de Citogenética, ICB, Universidade Federal do Pará, Belém, Pará, Brazil.,Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | | | - Julio Cesar Pieczarka
- Centro de Estudos Avançados da Biodiversidade, Laboratório de Citogenética, ICB, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Jorge Rissino
- Centro de Estudos Avançados da Biodiversidade, Laboratório de Citogenética, ICB, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Jorge C Pereira
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Malcolm Andrew Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Cleusa Yoshiko Nagamachi
- Centro de Estudos Avançados da Biodiversidade, Laboratório de Citogenética, ICB, Universidade Federal do Pará, Belém, Pará, Brazil.
| |
Collapse
|
14
|
Valeri MP, Tomazella IM, Duarte JM. Intrapopulation Chromosomal Polymorphism in Mazama gouazoubira (Cetartiodactyla; Cervidae): The Emergence of a New Species? Cytogenet Genome Res 2018; 154:147-152. [DOI: 10.1159/000488377] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 11/19/2022] Open
Abstract
Mazama gouazoubira is a small deer species widely distributed in South America. Previous studies have shown that this species presents intraspecific chromosomal polymorphisms, which could affect fertility due to the effects of chromosomal rearrangements on gamete formation. Important aspects regarding the karyotype evolution of this species and the genus remain undefined due to the lack of information concerning the causes of this chromosomal variation. Nineteen individuals belonging to the Mazama gouazoubira population located in the Pantanal were cytogenetically evaluated. Among the individuals analyzed, 9 had B chromosomes and 5 carried a heterozygous centric fusion (2n = 69 and FN = 70). In 3 individuals, the fusion occurred between chromosomes X and 16, in 1 individual between chromosomes 7 and 21, and in another individual between chromosomes 4 and 16. These striking polymorphisms could be explained by several hypotheses. One is that the chromosome rearrangements in this species are recent and not fixed in the population yet, and another hypothesis is that they represent a balanced polymorphism and that heterozygotes have an adaptive advantage. On the other hand, these polymorphisms may negatively influence fertility and raise questions about sustainability or reproductive isolation of the population.
Collapse
|
15
|
Veyrunes F, Perez J. X inactivation in a mammal species with three sex chromosomes. Chromosoma 2017; 127:261-267. [PMID: 29256059 DOI: 10.1007/s00412-017-0657-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 12/08/2017] [Accepted: 12/12/2017] [Indexed: 11/30/2022]
Abstract
X inactivation is a fundamental mechanism in eutherian mammals to restore a balance of X-linked gene products between XY males and XX females. However, it has never been extensively studied in a eutherian species with a sex determination system that deviates from the ubiquitous XX/XY. In this study, we explore the X inactivation process in the African pygmy mouse Mus minutoides, that harbours a polygenic sex determination with three sex chromosomes: Y, X, and a feminizing mutant X, named X*; females can thus be XX, XX*, or X*Y, and all males are XY. Using immunofluorescence, we investigated histone modification patterns between the two X chromosome types. We found that the X and X* chromosomes are randomly inactivated in XX* females, while no histone modifications were detected in X*Y females. Furthermore, in M. minutoides, X and X* chromosomes are fused to different autosomes, and we were able to show that the X inactivation never spreads into the autosomal segments. Evaluation of X inactivation by immunofluorescence is an excellent quantitative procedure, but it is only applicable when there is a structural difference between the two chromosomes that allows them to be distinguished.
Collapse
Affiliation(s)
- Frédéric Veyrunes
- Institut des Sciences de l'Evolution, ISEM UMR 5554 (CNRS / Université Montpellier / IRD / EPHE), Montpellier, France.
| | - Julie Perez
- Institut des Sciences de l'Evolution, ISEM UMR 5554 (CNRS / Université Montpellier / IRD / EPHE), Montpellier, France
| |
Collapse
|
16
|
Vieira-da-Silva A, Adega F, Guedes-Pinto H, Chaves R. LINE-1 distribution in six rodent genomes follow a species-specific pattern. J Genet 2016; 95:21-33. [PMID: 27019429 DOI: 10.1007/s12041-015-0595-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
L1 distribution in mammal's genomes is yet a huge riddle. However, these repetitive sequences were already found in all chromosomic regions, and in general, they seem to be nonrandomly distributed in the genome. It also seems that after insertion and when they are not deleterious, they are always involved in dynamic processes occurring on that particular chromosomic region. Furthermore, it seems that large-scale genome rearrangements and L1 activity and accumulation are somehow interconnected. In the present study, we analysed L1 genomic distribution in Tatera gambiana (Muridae, Gerbillinae), Acomys sp. (Muridae, Deomyinae), Cricetomys sp. (Nesomyidae, Cricetomyinae), Microtus arvalis (Cricetidae, Arvicolinae), Phodopus roborovskii and P. sungorus (Cricetidae, Cricetinae). All the species studied here seems to exhibit a species-specific pattern.Possible mechanisms, and processes involved in L1 distribution and preferential accumulation in certain regions are di scussed.
Collapse
Affiliation(s)
- A Vieira-da-Silva
- Department of Genetics and Biotechnology (DGB), Laboratory of Cytogenomics and Animal Genomics (CAG), University of Trάs-os-Montes and Alto Douro (UTAD), 5001, 801 Vila Real,
| | | | | | | |
Collapse
|
17
|
Murata C, Kuroki Y, Imoto I, Kuroiwa A. Ancestral Y-linked genes were maintained by translocation to the X and Y chromosomes fused to an autosomal pair in the Okinawa spiny rat Tokudaia muenninki. Chromosome Res 2016; 24:407-19. [DOI: 10.1007/s10577-016-9531-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/14/2016] [Indexed: 11/29/2022]
|
18
|
Meiotic behaviour of evolutionary sex-autosome translocations in Bovidae. Chromosome Res 2016; 24:325-38. [PMID: 27136937 DOI: 10.1007/s10577-016-9524-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/12/2016] [Accepted: 04/17/2016] [Indexed: 10/21/2022]
Abstract
The recurrent occurrence of sex-autosome translocations during mammalian evolution suggests common mechanisms enabling a precise control of meiotic synapsis, recombination and inactivation of sex chromosomes. We used immunofluorescence and FISH to study the meiotic behaviour of sex chromosomes in six species of Bovidae with evolutionary sex-autosome translocations (Tragelaphus strepsiceros, Taurotragus oryx, Tragelaphus imberbis, Tragelaphus spekii, Gazella leptoceros and Nanger dama ruficollis). The autosomal regions of fused sex chromosomes showed normal synapsis with their homologous counterparts. Synapsis in the pseudoautosomal region (PAR) leads to the formation of characteristic bivalent (in T. imberbis and T. spekii with X;BTA13/Y;BTA13), trivalent (in T. strepsiceros and T. oryx with X/Y;BTA13 and G. leptoceros with X;BTA5/Y) and quadrivalent (in N. dama ruficollis with X;BTA5/Y;BTA16) structures at pachynema. However, when compared with other mammals, the number of pachynema lacking MLH1 foci in the PAR was relatively high, especially in T. imberbis and T. spekii, species with both sex chromosomes involved in sex autosome translocations. Meiotic transcriptional inactivation of the sex-autosome translocations assessed by γH2AX staining was restricted to their gonosomal regions. Despite intraspecies differences, the evolutionary fixation of sex-autosome translocations among bovids appears to involve general mechanisms ensuring sex chromosome pairing, synapsis, recombination and inactivation.
Collapse
|
19
|
Lanzone C, Labaroni C, Suárez N, Rodríguez D, Herrera ML, Bolzán AD. Distribution of Telomeric Sequences (TTAGGG)n in Rearranged Chromosomes of Phyllotine Rodents (Cricetidae, Sigmodontinae). Cytogenet Genome Res 2016; 147:247-52. [DOI: 10.1159/000444602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2015] [Indexed: 11/19/2022] Open
Abstract
Phyllotines are sigmodontine rodents endemic to South America with broad genetic variability, Robertsonian polymorphisms being the most frequent. Moreover, this taxon includes a species with multiple sex chromosomes, which is infrequent in mammals. However, molecular cytogenetic techniques have never been applied to phyllotines to elucidate their karyotypic evolution. We studied the chromosomes of 4 phyllotine species using FISH with a pantelomeric probe (TTAGGG)n. Graomys griseoflavus, Eligmodontia puerulus, and E. morgani are polymorphic for Robertsonian translocations, whereas Salinomys delicatus possesses XX/ XY1Y2 sex chromosomes. Telomeric signals were detected at both ends of all chromosomes of the studied species. In S. delicatus interstitial telomeric sequences (ITS) were observed in the 3 major chromosome pairs, which are equidistant from one of the telomeres in these chromosomes. These results suggest that ITS are important in the reshuffling of the highly derived karyotype of S. delicatus. Considering the phylogeny of phyllotines, the Robertsonian rearrangements of G. griseoflavus, E. puerulus, and E. morgani possibly represent chromosome fusions which have occurred independently. The pericentromeric regions of the biarmed chromosomes of these species do not contain telomeric sequences characteristic for strict fusions of recent origin, suggesting a common pattern of telomeric repeat loss during chromosomal evolution of these rodents.
Collapse
|
20
|
Abstract
Chromosomal fusion plays a recurring role in the evolution of adaptations and reproductive isolation among species, yet little is known of the evolutionary drivers of chromosomal fusions. Because sex chromosomes (X and Y in male heterogametic systems, Z and W in female heterogametic systems) differ in their selective, mutational, and demographic environments, those differences provide a unique opportunity to dissect the evolutionary forces that drive chromosomal fusions. We estimate the rate at which fusions between sex chromosomes and autosomes become established across the phylogenies of both fishes and squamate reptiles. Both the incidence among extant species and the establishment rate of Y-autosome fusions is much higher than for X-autosome, Z-autosome, or W-autosome fusions. Using population genetic models, we show that this pattern cannot be reconciled with many standard explanations for the spread of fusions. In particular, direct selection acting on fusions or sexually antagonistic selection cannot, on their own, account for the predominance of Y-autosome fusions. The most plausible explanation for the observed data seems to be (a) that fusions are slightly deleterious, and (b) that the mutation rate is male-biased or the reproductive sex ratio is female-biased. We identify other combinations of evolutionary forces that might in principle account for the data although they appear less likely. Our results shed light on the processes that drive structural changes throughout the genome.
Collapse
|
21
|
Nanger, Eudorcas, Gazella, and Antilope form a well-supported chromosomal clade within Antilopini (Bovidae, Cetartiodactyla). Chromosoma 2014; 124:235-47. [PMID: 25416455 DOI: 10.1007/s00412-014-0494-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/05/2014] [Accepted: 11/05/2014] [Indexed: 10/24/2022]
Abstract
The evolutionary clade comprising Nanger, Eudorcas, Gazella, and Antilope, defined by an X;BTA5 translocation, is noteworthy for the many autosomal Robertsonian fusions that have driven the chromosome number variation from 2n = 30 observed in Antilope cervicapra, to the 2n = 58 in present Eudorcas thomsoni and Eudorcas rufifrons. This work reports the phylogenetic relationships within the Antilopini using comprehensive cytogenetic data from A. cervicapra, Gazella leptoceros, Nanger dama ruficollis, and E. thomsoni together with corrected karyotypic data from an additional nine species previously reported in the literature. Fluorescence in situ hybridization using BAC and microdissected cattle painting probes, in conjunction with differential staining techniques, provide the following: (i) a detailed analysis of the E. thomsoni chromosomes, (ii) the identification and fine-scale analysis the BTA3 orthologue in species of Antilopini, and (iii) the location of the pseudoautosomal regions on sex chromosomes of the four species. Our phylogenetic analysis of the chromosomal data supports monophyly of Nanger and Eudorcas and suggests an affiliation between A. cervicapra and some of the Gazella species. This renders Gazella paraphyletic and emphasizes a closer relationship between Antilope and Gazella than what has previously been considered.
Collapse
|
22
|
Veyrunes F, Perez J, Borremans B, Gryseels S, Richards LR, Duran A, Chevret P, Robinson TJ, Britton-Davidian J. A new cytotype of the African pygmy mouse Mus minutoides in Eastern Africa. Implications for the evolution of sex-autosome translocations. Chromosome Res 2014; 22:533-43. [PMID: 25159220 DOI: 10.1007/s10577-014-9440-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 07/31/2014] [Accepted: 08/17/2014] [Indexed: 11/27/2022]
Abstract
The African pygmy mice (genus Mus, subgenus Nannomys) are recognized for their highly conserved morphology but extensive chromosomal diversity, particularly involving sex-autosome translocations, one of the rarest chromosomal rearrangements among mammals. It has been shown that in the absence of unambiguous diagnostic morphological traits, sex-autosome translocations offer accurate taxonomic markers. For example, in Mus minutoides, irrespective of the diploid number (which ranges from 2n = 18 to 34), all specimens possess the sex-autosome translocations (X.1) and (Y.1) that are unique to this species. In this study, we describe a new cytotype that challenges this view. Males are characterized by the translocation (Y.1) only, while females carry no sex-autosome translocation, the X chromosome being acrocentric. Hence, although sex-autosome translocations (X.1) and (Y.1) are still diagnostic when one or both are present, their absence does not rule out M. minutoides. This cytotype has a large distribution, with specimens found in Tanzania and in the eastern part of South Africa. The nonpervasive distribution of Rb(X.1) provides an opportunity to investigate different evolutionary scenarios of sex-autosome translocations using a phylogenetic framework and the distribution of telomeric repeats. The results tend to support a scenario involving a reversal event, i.e., fusion then fission of Rb(X.1), and highlighted the existence of a new X1X1X2X2/X1X2Y sex chromosome system, confirming the remarkable diversity of neo-sex chromosomes and sex determination systems in the African pygmy mice.
Collapse
Affiliation(s)
- F Veyrunes
- Institut des Sciences de l'Evolution de Montpellier, Université Montpellier 2, UMR CNRS 5554, Montpellier, France,
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Arcanjo A, Cabral-de-Mello DC, Martins C, de Cássia de Moura R, de Souza MJ. Chromosomal diversification of diploid number, heterochromatin and rDNAs in two species of Phanaeus beetles (Scarabaeidae, Scarabaeinae). Genet Mol Biol 2013; 36:341-6. [PMID: 24130440 PMCID: PMC3795170 DOI: 10.1590/s1415-47572013005000031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 04/24/2013] [Indexed: 12/31/2022] Open
Abstract
The genus Phanaeus is included in the tribe Phanaeini, one of the most diverse tribes within the subfamily Scarabaeinae in terms of chromosomal characteristics. However, so far the species of this genus were not studied with differential cytogenetic techniques, limiting any inference of the probable mechanisms responsible for this diversity. In this work, several techniques were applied with the aim of cytogenetically characterizing two Phanaeus species. The karyotype found for Phanaeus (Notiophanaeus) chalcomelas was 2n = 12, neo-XY, and that of P. (N.) splendidulus was 2n = 20, Xyp, considered primitive for the family Scarabaeidae. The chromosomes of both species showed a high amount of constitutive heterochromatin (CH), with blocks rich in base pairs GC (CMA3+). Moreover, in P. (N.) chalcomelas the marks revealed by C-banding and fluorochrome staining were different in size, showing CH variability. Sites of 18S ribosomal DNA (rDNA) were identified in one autosomal pair of P. (N.) chalcomelas and in five autosomal pairs of P. (N.) splendidulus. On the other hand, only one autosomal pair exhibited 5S rDNA sequences in these species. The results suggest that the karyotype differentiation of the Phanaeus species studied here involved pericentric inversions and centric fusions, as well as mechanisms related to amplification and dispersion of CH and rDNA sequences.
Collapse
Affiliation(s)
- Amanda Arcanjo
- Departamento de Genética, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Recife, PE, Brazil . ; Departamento de Biologia, Instituto de Ciências Biológicas, Universidade de Pernambuco, Recife, PE, Brazil
| | | | | | | | | |
Collapse
|
24
|
Pieczarka JC, Gomes AJB, Nagamachi CY, Rocha DCC, Rissino JD, O'Brien PCM, Yang F, Ferguson-Smith MA. A phylogenetic analysis using multidirectional chromosome painting of three species (Uroderma magnirostrum, U. bilobatum and Artibeus obscurus) of subfamily Stenodermatinae (Chiroptera-Phyllostomidae). Chromosome Res 2013; 21:383-92. [PMID: 23775139 DOI: 10.1007/s10577-013-9365-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 05/18/2013] [Accepted: 05/28/2013] [Indexed: 11/30/2022]
Abstract
The species of genera Uroderma and Artibeus are medium-sized bats belonging to the family Phyllostomidae and subfamily Stenodermatinae (Mammalia, Chiroptera) from South America. They have a wide distribution in the Neotropical region, with two currently recognized species in Uroderma and approximately 20 species in Artibeus. These two genera have different rates of chromosome evolution, with Artibeus probably having retained the ancestral karyotype for the subfamily. We used whole chromosome paint probe sets from Carollia brevicauda and Phyllostomus hastatus on Uroderma magnirostrum, Uroderma bilobatum, and Artibeus obscurus. With the aim of testing the previous phylogenies of these bats using cytogenetics, we compared these results with published painting maps on Phyllostomidae. The genome-wide comparative maps based on chromosome painting and chromosome banding reveal the chromosome forms that characterize each taxonomic level within the Phyllostomidae and show the chromosome evolution of this family. Based on this, we are able to suggest an ancestral karyotype for Phyllostomidae. Our cladistic analysis is an independent confirmation using multidirectional chromosome painting of the previous Phyllostomidae phylogenies.
Collapse
Affiliation(s)
- J C Pieczarka
- Laboratório de Citogenética, ICB, UFPA, Belem, Brazil.
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Yoshida K, Kitano J. The contribution of female meiotic drive to the evolution of neo-sex chromosomes. Evolution 2012; 66:3198-208. [PMID: 23025609 PMCID: PMC3494977 DOI: 10.1111/j.1558-5646.2012.01681.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 04/22/2012] [Indexed: 11/28/2022]
Abstract
Sex chromosomes undergo rapid turnover in certain taxonomic groups. One of the mechanisms of sex chromosome turnover involves fusions between sex chromosomes and autosomes. Sexual antagonism, heterozygote advantage, and genetic drift have been proposed as the drivers for the fixation of this evolutionary event. However, all empirical patterns of the prevalence of multiple sex chromosome systems across different taxa cannot be simply explained by these three mechanisms. In this study, we propose that female meiotic drive may contribute to the evolution of neo-sex chromosomes. The results of this study showed that in mammals, the XY(1) Y(2) sex chromosome system is more prevalent in species with karyotypes of more biarmed chromosomes, whereas the X(1) X(2) Y sex chromosome system is more prevalent in species with predominantly acrocentric chromosomes. In species where biarmed chromosomes are favored by female meiotic drive, X-autosome fusions (XY(1) Y(2) sex chromosome system) will be also favored by female meiotic drive. In contrast, in species with more acrocentric chromosomes, Y-autosome fusions (X(1) X(2) Y sex chromosome system) will be favored just because of the biased mutation rate toward chromosomal fusions. Further consideration should be given to female meiotic drive as a mechanism in the fixation of neo-sex chromosomes.
Collapse
Affiliation(s)
- Kohta Yoshida
- Ecological Genetics Laboratory, Center for Frontier Research, National Institute of GeneticsYata 1111, Mishima, Shizuoka 411–8540, Japan
| | - Jun Kitano
- Ecological Genetics Laboratory, Center for Frontier Research, National Institute of GeneticsYata 1111, Mishima, Shizuoka 411–8540, Japan
- PRESTO, Japan Science and Technology Agency, Honcho KawaguchiSaitama 332-0012, Japan
| |
Collapse
|
26
|
Systematics and evolution of the African pygmy mice, subgenus Nannomys: A review. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2012. [DOI: 10.1016/j.actao.2012.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
27
|
Romanenko SA, Volobouev V. Non-Sciuromorph rodent karyotypes in evolution. Cytogenet Genome Res 2012; 137:233-45. [PMID: 22699115 DOI: 10.1159/000339294] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Rodents are, taxonomically, the most species-rich mammalian order. They display a series of special genomic features including the highest karyotypic diversity, frequent occurrence of complex intraspecies chromosome variability, and a variety of unusual chromosomal sex determination mechanisms not encountered in other mammalian taxa. Rodents also have an abundance of cytochemically heterogeneous heterochromatin. There are also instances of extremely rapid karyotype reorganization and speciation not accompanied by significant genetic differentiation. All these peculiarities make it clear that a detailed study of rodent genomic evolution is indispensable to understand the mode and tempo of mammalian evolution. The aim of this review is to update the data obtained by classical and molecular cytogenetics as well as comparative genomics in order to outline the range of old and emerging problems that remain to be resolved.
Collapse
Affiliation(s)
- S A Romanenko
- Institute of Molecular and Cellular Biology, SB RAS, Novosibirsk, Russia.
| | | |
Collapse
|
28
|
The Y chromosome of the Okinawa spiny rat, Tokudaia muenninki, was rescued through fusion with an autosome. Chromosome Res 2012; 20:111-25. [PMID: 22198613 DOI: 10.1007/s10577-011-9268-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The genus Tokudaia comprises three species, two of which have lost their Y chromosome and have an XO/XO sex chromosome constitution. Although Tokudaia muenninki (Okinawa spiny rat) retains the Y chromosome, both sex chromosomes are unusually large. We conducted a molecular cytogenetic analysis to characterize the sex chromosomes of T. muenninki. Using cross-species fluorescence in situ hybridization (Zoo-FISH), we found that both short arms of the T. muenninki sex chromosomes were painted by probes from mouse chromosomes 11 and 16. Comparative genomic hybridization analysis was unable to detect sex-specific regions in the sex chromosomes because both sex probes highlighted the large heterochromatic blocks on the Y chromosome as well as five autosomal pairs. We then performed comparative FISH mapping using 29 mouse complementary DNA (cDNA) clones of the 22 X-linked genes and the seven genes linked to mouse chromosome 11 (whose homologue had fused to the sex chromosomes), and FISH mapping using two T. muenninki cDNA clones of the Y-linked genes. This analysis revealed that the ancestral gene order on the long arm of the X chromosome and the centromeric region of the short arm of the Y chromosome were conserved. Whereas six of the mouse chromosome 11 genes were also mapped to Xp and Yp, in addition, one gene, CBX2, was also mapped to Xp, Yp, and chromosome 14 in T. muenninki. CBX2 is the candidate gene for the novel sex determination system in the two other species of Tokudaia, which lack a Y chromosome and SRY gene. Overall, these results indicated that the Y chromosome of T. muenninki avoided a loss event, which occurred in an ancestral lineage of T. osimensis and T. tokunoshimensis, through fusion with an autosome. Despite retaining the Y chromosome, sex determination in T. muenninki might not follow the usual mammalian pattern and deserves further investigation.
Collapse
|
29
|
Cernohorska H, Kubickova S, Vahala J, Rubes J. Molecular insights into X;BTA5 chromosome rearrangements in the tribe Antilopini (Bovidae). Cytogenet Genome Res 2012; 136:188-98. [PMID: 22327909 DOI: 10.1159/000336248] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2011] [Indexed: 01/30/2023] Open
Abstract
For a clade that includes Antilope, Gazella,Nanger and Eudorcas (Antilopinae), X;BTA5 translocation is a synapomorphy. Using a combination of fluorescence in situ hybridization (FISH) probes and polymerase chain reaction techniques, we provide (i) the first insight into the X;BTA5 architecture which differs in the species under study: Antilope cervicapra (genus Antilope), Gazella leptoceros (genus Gazella) and Nanger dama ruficollis (genus Nanger), (ii) determination of interstitial satellite DNA at the X;BTA5 junctions, and (iii) determination of repetitive sequences occupying constitutive heterochromatin of Xp arms in the studied species. The distribution of 2 repetitive DNA families in the centromeric regions of all chromosomes has been investigated by FISH with probes representing satellite I and satellite II DNA in all studied species. In this context, we discuss a markedly smaller centromere in the BTA5 (Y2) unfused chromosomes in males in the XY1Y2 determining system in comparison with other acrocentrics. An analysis of karyotypic data described in current published studies revealed a disparity with the data determined by FISH. In this report, we document chromosomal fusions in the 3 species mentioned resulting from FISH with painting probes prepared from cattle (Bos taurus). The number and chromosomal location of nucleolus organizer regions were determined by FISH. In the present study, we emphasize the importance of chromosomal rearrangement verification, particularly, if they are used for phylogenetic analysis.
Collapse
|
30
|
Badenhorst D, Dobigny G, Robinson TJ. Karyotypic evolution of hapalomys inferred from chromosome painting: a detailed characterization contributing new insights into the ancestral murinae karyotype. Cytogenet Genome Res 2012; 136:83-8. [PMID: 22222239 DOI: 10.1159/000335286] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2011] [Indexed: 11/19/2022] Open
Abstract
We report on the construction of a comparative chromosome map between the emblematic laboratory rat, Rattus norvegicus (RNO), and Delacour's Marmoset rat, Hapalomys delacouri (HDE), based on cross-species fluorescence in situ hybridization with R. norvegicus painting probes. Sixteen R. norvegicus chromosomes (RNO 3-6, 8, 10-15, 17-20, and X) were retained in their entirety (as a conserved block or as a single chromosome) in the H. delacouri genome. The remaining 5 R. norvegicus chromosomes (RNO 1, 2, 7, 9, and 16) produced 2 signals in the H. delacouri karyotype. Our analysis allowed the detection of an X-autosome translocation between RNO X and 11 that occurred convergently in an unrelated species, Bandicota savilei, and a single B chromosome that accounts for the 2n = 48 karyotype observed in this specimen. In total, the rat chromosome paints revealed 27 segments of conserved synteny in H. delacouri. The analysis showed 7 NOR bearing pairs in H. delacouri (HDE 1, 3, 6, 7, 8, 10, and 13) and the occurrence of an interstitial telomeric signal at the centromeric regions of 8 H. delacouri chromosomes (HDE 3, 10, 11, 12, 13, 16, 19, and 22). These data, together with published comparative maps, enabled a revision of the previously postulated murine ancestral condition suggesting that it probably comprised a wholly acrocentric karyotype with 2n = 46-50.
Collapse
Affiliation(s)
- D Badenhorst
- Evolutionary Genomics Group, University of Stellenbosch, Botany and Zoology Department, Stellenbosch, South Africa
| | | | | |
Collapse
|
31
|
Lanzone C, Rodríguez D, Cuello P, Albanese S, Ojeda A, Chillo V, Martí DA. XY1Y2 chromosome system in Salinomys delicatus (Rodentia, Cricetidae). Genetica 2011; 139:1143-7. [PMID: 22105874 DOI: 10.1007/s10709-011-9616-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 11/08/2011] [Indexed: 10/15/2022]
Abstract
Salinomys delicatus is considered a rare species due to its restricted and patchy distribution, poor records and low abundances. It is also the phyllotine with the lowest known diploid chromosome number (2n = 18), however its sex chromosome system has never been described. Here, we studied the chromosomes of six females and three males with bands G, C, DAPI/CMA(3) and meiosis. In males, the chromosome number was 2n = 19, with one large metacentric X-chromosome and two medium-sized acrocentrics absent in females. The karyotype of females was the same as previously described (2n = 18, FN = 32), with X-chromosomes being metacentric and the largest elements of the complement. In males, the two acrocentrics and the large metacentric form a trivalent in meiotic prophase. This indicates that S. delicatus has XY(1)Y(2) sex chromosomes, which is confirmed by G and DAPI bands. Constitutive heterochromatin (CH) is restricted to small pericentromeric blocks in all chromosomes. The X-chromosome shows the largest block of centromeric CH, which could favor the establishment of this X-autosome translocation. This sex chromosome system is rare in mammals and, compared with other phyllotine rodents, S. delicatus seems to have undergone a major chromosome restructuring during its karyotypic evolution.
Collapse
Affiliation(s)
- C Lanzone
- Grupo de Investigaciones de la Biodiversidad, IADIZA, CONICET, CCT-Mendoza, CC 507, CP5500 Mendoza, Argentina.
| | | | | | | | | | | | | |
Collapse
|
32
|
Chromosomal evolution in Rattini (Muridae, Rodentia). Chromosome Res 2011; 19:709-27. [PMID: 21850459 DOI: 10.1007/s10577-011-9227-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
The Rattini (Muridae, Murinae) includes the biologically important model species Rattus norvegicus (RNO) and represents a group of rodents that are of clinical, agricultural and epidemiological importance. We present a comparative molecular cytogenetic investigation of ten Rattini species representative of the genera Maxomys, Leopoldamys, Niviventer, Berylmys, Bandicota and Rattus using chromosome banding, cross-species painting (Zoo-fluorescent in situ hybridization or FISH) and BAC-FISH mapping. Our results show that these taxa are characterised by slow to moderate rates of chromosome evolution that contrasts with the extensive chromosome restructuring identified in most other murid rodents, particularly the mouse lineage. This extends to genomic features such as NOR location (for example, NORs on RNO 3 are present on the corresponding chromosomes in all species except Bandicota savilei and Niviventer fulvescens, and the NORs on RNO 10 are conserved in all Rattini with the exception of Rattus). The satellite I DNA family detected and characterised herein appears to be taxon (Rattus) specific, and of recent origin (consistent with a feedback model of satellite evolution). BAC-mapping using clones that span regions responsible for the morphological variability exhibited by RNO 1, 12 and 13 (acrocentric/submetacentric) and their orthologues in Rattus species, demonstrated that the differences are most likely due to pericentric inversions as exemplified by data on Rattus tanezumi. Chromosomal characters detected using R. norvegicus and Maxomys surifer whole chromosome painting probes were mapped to a consensus sequence-based phylogenetic tree thus allowing an objective assessment of ancestral states for the reconstruction of the putative Rattini ancestral karyotype. This is thought to have comprised 46 chromosomes that, with the exception of a single pair of metacentric autosomes, were acrocentric in morphology.
Collapse
|
33
|
|
34
|
Richards LR, Rambau RV, Lamb JM, Taylor PJ, Yang F, Schoeman MC, Goodman SM. Cross-species chromosome painting in bats from Madagascar: the contribution of Myzopodidae to revealing ancestral syntenies in Chiroptera. Chromosome Res 2010; 18:635-53. [PMID: 20596765 DOI: 10.1007/s10577-010-9139-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 05/24/2010] [Accepted: 05/31/2010] [Indexed: 11/25/2022]
Abstract
The chiropteran fauna of Madagascar comprises eight of the 19 recognized families of bats, including the endemic Myzopodidae. While recent systematic studies of Malagasy bats have contributed to our understanding of the morphological and genetic diversity of the island's fauna, little is known about their cytosystematics. Here we investigate karyotypic relationships among four species, representing four families of Chiroptera endemic to the Malagasy region using cross-species chromosome painting with painting probes of Myotis myotis: Myzopodidae (Myzopoda aurita, 2n = 26), Molossidae (Mormopterus jugularis, 2n = 48), Miniopteridae (Miniopterus griveaudi, 2n = 46), and Vespertilionidae (Myotis goudoti, 2n = 44). This study represents the first time a member of the family Myzopodidae has been investigated using chromosome painting. Painting probes of M. myotis were used to delimit 29, 24, 23, and 22 homologous chromosomal segments in the genomes of M. aurita, M. jugularis, M. griveaudi, and M. goudoti, respectively. Comparison of GTG-banded homologous chromosomes/chromosomal segments among the four species revealed the genome of M. aurita has been structured through 14 fusions of chromosomes and chromosomal segments of M. myotis chromosomes leading to a karyotype consisting solely of bi-armed chromosomes. In addition, chromosome painting revealed a novel X-autosome translocation in M. aurita. Comparison of our results with published chromosome maps provided further evidence for karyotypic conservatism within the genera Mormopterus, Miniopterus, and Myotis. Mapping of chromosomal rearrangements onto a molecular consensus phylogeny revealed ancestral syntenies shared between Myzopoda and other bat species of the infraorders Pteropodiformes and Vespertilioniformes. Our study provides further evidence for the involvement of Robertsonian (Rb) translocations and fusions/fissions in chromosomal evolution within Chiroptera.
Collapse
Affiliation(s)
- Leigh R Richards
- School of Biological and Conservation Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa.
| | | | | | | | | | | | | |
Collapse
|
35
|
Multiple copies of SRY on the large Y chromosome of the Okinawa spiny rat, Tokudaia muenninki. Chromosome Res 2010; 18:623-34. [DOI: 10.1007/s10577-010-9142-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/08/2010] [Accepted: 06/08/2010] [Indexed: 01/19/2023]
|
36
|
Mlynarski EE, Obergfell C, Dewey MJ, O'Neill RJ. A unique late-replicating XY to autosome translocation in Peromyscus melanophrys. Chromosome Res 2010; 18:179-89. [PMID: 20177772 DOI: 10.1007/s10577-010-9113-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 01/15/2010] [Indexed: 11/25/2022]
Abstract
We report on the characterization of the Peromyscus melanophrys karyotype and sex chromosome system. Classic studies reported the sex chromosome system of this species may be as complex as an X(1)X(1)X(2)X(2)/X(1)X(2)Y(1)Y(2) and provided conflicting identification of the X chromosome. Using Peromyscus maniculatus chromosome paints, we have positively identified the sex chromosomes and clarified the sex determining system that once perplexed Peromyscus researchers. The sex chromosomes are characterized by a unique autosomal translocation of DNA shared between both the X and Y chromosomes. The translocated material is late replicating and heterochromatic yet retains the active chromatin conformation. Thus, autosomal regions derived from translocations involving repeat-rich material may retain some epigenetic marks specific to the sex chromosomes despite loss of epigenetic silencing activity.
Collapse
Affiliation(s)
- Elisabeth E Mlynarski
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, 06269, USA
| | | | | | | |
Collapse
|
37
|
Barakat TS, Gribnau J. X chromosome inactivation and embryonic stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 695:132-54. [PMID: 21222204 DOI: 10.1007/978-1-4419-7037-4_10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
X chromosome inactivation (XCI) is a process required to equalize the dosage of X-encoded genes between female and male cells. XCI is initiated very early during female embryonic development or upon differentiation of female embryonic stem (ES) cells and results in inactivation of one X chromosome in every female somatic cell. The regulation of XCI involves factors that also play a crucial role in ES cell maintenance and differentiation and the XCI process therefore provides a beautiful paradigm to study ES cell biology. In this chapter we describe the important cis and trans acting regulators of XCI and introduce the models that have been postulated to explain initiation of XCI in female cells only. We also discuss the proteins involved in the establishment of the inactive X chromosome and describe the different chromatin modifications associated with the inactivation process. Finally, we describe the potential of mouse and human ES and induced pluripotent stem (iPS) cells as model systems to study the XCI process.
Collapse
Affiliation(s)
- Tahsin Stefan Barakat
- Department of Reproduction and Development, University Medical Center, Room Ee 09-71, Erasmus MC, 3015 GE, Rotterdam, Netherlands
| | | |
Collapse
|
38
|
Cantrell MA, Carstens BC, Wichman HA. X chromosome inactivation and Xist evolution in a rodent lacking LINE-1 activity. PLoS One 2009; 4:e6252. [PMID: 19603076 PMCID: PMC2705805 DOI: 10.1371/journal.pone.0006252] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 05/28/2009] [Indexed: 02/05/2023] Open
Abstract
Dosage compensation in eutherian mammals occurs by inactivation of one X chromosome in females. Silencing of that X chromosome is initiated by Xist, a large non-coding RNA, whose coating of the chromosome extends in cis from the X inactivation center. LINE-1 (L1) retrotransposons have been implicated as possible players for propagation of the Xist signal, but it has remained unclear whether they are essential components. We previously identified a group of South American rodents in which L1 retrotransposition ceased over 8 million years ago and have now determined that at least one species of these rodents, Oryzomys palustris, still retains X inactivation. We have also isolated and analyzed the majority of the Xist RNA from O. palustris and a sister species retaining L1 activity, Sigmodon hispidus, to determine if evolution in these sequences has left signatures that might suggest a critical role for L1 elements in Xist function. Comparison of rates of Xist evolution in the two species fails to support L1 involvement, although other explanations are possible. Similarly, comparison of known repeats and potential RNA secondary structures reveals no major differences with the exception of a new repeat in O. palustris that has potential to form new secondary structures.
Collapse
Affiliation(s)
- Michael A. Cantrell
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Bryan C. Carstens
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Holly A. Wichman
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- * E-mail:
| |
Collapse
|
39
|
Rubes J, Kubickova S, Pagacova E, Cernohorska H, Di Berardino D, Antoninova M, Vahala J, Robinson TJ. Phylogenomic study of spiral-horned antelope by cross-species chromosome painting. Chromosome Res 2008; 16:935-47. [PMID: 18704723 DOI: 10.1007/s10577-008-1250-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 06/23/2008] [Accepted: 06/23/2008] [Indexed: 11/28/2022]
Abstract
Chromosomal homologies have been established between cattle (Bos taurus, 2n = 60) and eight species of spiral-horned antelope, Tribe Tragelaphini: Nyala (Tragelaphus angasii, 2n = 55male/56female), Lesser kudu (T. imberbis, 2n = 38male,female), Bongo (T. eurycerus, 2n = 33male/34female), Bushbuck (T. scriptus, 2n = 33male/34female), Greater kudu (T. strepsiceros, 2n = 31male/32female), Sitatunga (T. spekei, 2n = 30male,female) Derby eland (Taurotragus derbianus 2n = 31male/32female) and Common eland (T. oryx 2n = 31male/32female). Chromosomes involved in centric fusions in these species were identified using a complete set of cattle painting probes generated by laser microdissection. Our data support the monophyly of Tragelaphini and a clade comprising T. scriptus, T. spekei, T. euryceros and the eland species T. oryx and T. derbianus, findings that are largely in agreement with sequence-based molecular phylogenies. In contrast, our study suggests that the arid adaptiveness of T. oryx and T. derbianus is recent. Finally, we have identified the presence of the rob(1;29) fusion as an evolutionary marker in most of the tragelaphid species investigated. This rearrangement is associated with reproductive impairment in cattle and raises questions whether subtle distinctions in breakpoint location or differential rescue during meiosis underpin the different outcomes detected among these lineages.
Collapse
Affiliation(s)
- Jiri Rubes
- Department of Genetics and Reproduction, Veterinary Research Institute, Brno, Czech Republic.
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Deuve JL, Bennett NC, Britton-Davidian J, Robinson TJ. Chromosomal phylogeny and evolution of the African mole-rats (Bathyergidae). Chromosome Res 2008; 16:57-74. [PMID: 18293105 DOI: 10.1007/s10577-007-1200-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The subterranean African mole-rats (Family Bathyergidae) show considerable variation in their diploid numbers, but there is limited understanding of the events that shaped the extant karyotypes. Here we investigate chromosomal evolution in specimens representative of six genera and an outgroup species, the cane rat Thryonomys swinderianus, using flow-sorted painting probes isolated from the naked mole-rat, Heterocephalus glaber (2n = 60). A chromosomal phylogeny based on the cladistic analysis of adjacent syntenies detected by cross-species chromosome painting was not consistent with that obtained using DNA sequences due, in large part, to the conserved nature of the Bathyergus, Georychus and Cryptomys karyotypes. In marked contrast, the Fukomys and Heliophobius species showed extensive chromosome reshuffling, permitting their analysis by a computational approach that has conventionally been employed in comparative genomic studies for retrieving phylogenetic information based on DNA sequence or gene order data. Using the multiple genome rearrangements (MGR) algorithm and chromosomal rearrangement data detected among F. damarensis, F. darlingi, F. mechowi and the sister taxa B. janetta and Heliophobius argenteocinereus, cytogenetic support for the monophyly of Fukomys and a sister association for F. darlingi + F. damarensis was retrieved, mirroring the published sequence-based topology. We show that F. damarensis, a lineage adapted to arid and climatically unpredictable environments in Southern Africa, is characterized by a large number of fissions the fixation of which has probably been favoured by environmental factors and/or its particular eusocial structure.
Collapse
Affiliation(s)
- J L Deuve
- Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, Matieland, 7602, South Africa
| | | | | | | |
Collapse
|
41
|
Dissection of a Y-autosome translocation in Cryptomys hottentotus (Rodentia, Bathyergidae) and implications for the evolution of a meiotic sex chromosome chain. Chromosoma 2007; 117:211-7. [PMID: 18094986 DOI: 10.1007/s00412-007-0140-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 11/20/2007] [Accepted: 11/28/2007] [Indexed: 11/27/2022]
Abstract
We describe the outcome of a comprehensive cytogenetic survey of the common mole-rat, Cryptomys hottentotus, based on G and C banding, fluorescence in situ hybridisation and the analysis of meiotic chromosomes using immunostaining of proteins involved in the formation of synaptonemal complex (SCP1 and SCP3). We identified the presence of a Y-autosome translocation that is responsible for a fixed diploid number difference between males (2n = 53) and females (2n = 54), a character that likely defines the C. hottentotus lineage. Immunostaining, combined with C banding of spermatocytes, revealed a linearised sex trivalent with X(1) at one end and X(2) at the other, with evidence of reduced recombination between Y and X(2) that seems to be heterochromatin dependant in the C. hottentotus lineage. We suggest that this could depict the likely initial step in the differentiation of a true neo-X, and that this may mimic an early stage in the mammalian meiotic chain formation, an evolutionary process that has been taken to an extreme in a monotreme mammal, the platypus.
Collapse
|
42
|
Yen ZC, Meyer IM, Karalic S, Brown CJ. A cross-species comparison of X-chromosome inactivation in Eutheria. Genomics 2007; 90:453-63. [PMID: 17728098 DOI: 10.1016/j.ygeno.2007.07.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 05/25/2007] [Accepted: 07/04/2007] [Indexed: 10/22/2022]
Abstract
Mammalian X-chromosome inactivation achieves dosage compensation between the sexes by the silencing of one X chromosome in females. In Eutheria, X inactivation is initiated by the large noncoding RNA Xist; however, it is unknown how this RNA results in silencing of the chromosome or why, at least in humans, many genes escape silencing in somatic cells. We have sequenced the coast mole Xist gene and compared the Xist RNA sequence among seven eutherians to provide insight into the structure of the RNA and origins of the gene. Using DNA methylation of promoter sequences to assess whether genes are silenced in females we report the inactivation status of seven X-linked genes in humans and mice as well as two additional eutherians, the mole and the cow, providing evidence that escape from inactivation is common among Eutheria.
Collapse
Affiliation(s)
- Ziny C Yen
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | | | | | | |
Collapse
|
43
|
Waters PD, Ruiz-Herrera A, Dobigny G, Garcia Caldès M, Robinson TJ. Sex chromosomes of basal placental mammals. Chromosoma 2007; 116:511-8. [PMID: 17602234 DOI: 10.1007/s00412-007-0116-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 06/06/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
Placental (eutherian) mammals are currently classified into four superordinal clades (Afrotheria, Xenarthra, Laurasiatheria and Supraprimates) of which one, the Afrotheria (a unique lineage of African origin), is generally considered to be basal. Therefore, Afrotheria provide a pivotal evolutionary link for studying fundamental differences between the sex chromosomes of human/mouse (both representatives of Supraprimates and the index species for studies of sex chromosomes) and those of the distantly related marsupials. In this study, we use female fibroblasts to investigate classical features of X chromosome inactivation including replication timing of the X chromosomes and Barr body formation. We also examine LINE-1 accumulation on the X chromosomes of representative afrotherians and look for evidence of a pseudoautosomal region (PAR). Our results demonstrate that asynchronous replication of the X chromosomes is common to Afrotheria, as with other mammals, and Barr body formation is observed across all Placentalia, suggesting that mechanisms controlling this evolved before their radiation. Finally, we provide evidence of a PAR (which marsupials lack) and demonstrate that LINE1 is accumulated on the afrotherian and xenarthran X, although this is probably not due to transposition events in a common ancestor, but rather ongoing selection to retain recently inserted LINE1 on the X.
Collapse
Affiliation(s)
- Paul D Waters
- Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
| | | | | | | | | |
Collapse
|
44
|
Veyrunes F, Watson J, Robinson TJ, Britton-Davidian J. Accumulation of rare sex chromosome rearrangements in the African pygmy mouse, Mus (Nannomys) minutoides: a whole-arm reciprocal translocation (WART) involving an X-autosome fusion. Chromosome Res 2007; 15:223-30. [PMID: 17285252 DOI: 10.1007/s10577-006-1116-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 11/28/2006] [Accepted: 11/28/2006] [Indexed: 01/05/2023]
Abstract
Although sex chromosomes are generally the most conserved elements of the mammalian karyotype, those of African pygmy mice show three extraordinary deviations from the norm: (a) asynaptic sex chromosomes, (b) multiple sex-autosome fusions, and (c) modifications of sex determination in some populations/species. In this study we identified, in two sex-reversed females of Mus (Nannomys) minutoides, a fourth rare sex chromosome change: a spontaneous whole-arm reciprocal translocation (WART) between an autosomal Robertsonian pair Rb(13.16) and the sex-autosome fusion Rb(X.1). This represents one of the very few reported cases of WARTs in natura within mammals, and is the first one to involve sex chromosomes. Hence, this finding offers new insights into the mechanisms of chromosomal differentiation in African pygmy mice, as WARTs may have contributed to the extensive diversity not only of autosomal Robertsonian fusions, but also of sex-autosome translocations. More widely, these results provide additional support to previous studies on the house mouse and the common shrew which indirectly inferred the role of WARTs in their karyotypic evolution, and may even help to understand how the fascinating 10 sex chromosome chain of the platypus might have evolved. This accumulation of rare sex chromosome changes in single specimens is, to our knowledge, exceptional among mammals.
Collapse
Affiliation(s)
- Frédéric Veyrunes
- Institut des Sciences de l'Evolution (UMR5554), Génétique & Environnement, Université Montpellier II, Montpellier, France.
| | | | | | | |
Collapse
|
45
|
Deuve JL, Bennett NC, O'Brien PCM, Ferguson-Smith MA, Faulkes CG, Britton-Davidian J, Robinson TJ. Complex evolution of X and Y autosomal translocations in the giant mole-rat, Cryptomys mechowi (Bathyergidae). Chromosome Res 2006; 14:681-91. [PMID: 16964575 DOI: 10.1007/s10577-006-1080-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 06/25/2006] [Accepted: 06/25/2006] [Indexed: 10/24/2022]
Abstract
Cross-species chromosome painting was used to determine homologous chromosomal regions between two species of mole-rat, the naked mole-rat, Heterocephalus glaber (2n = 60), and the giant mole-rat, Cryptomys mechowi (2n = 40), using flow-sorted painting probes representative of all but two of the H. glaber chromosomal complement. In total 43 homologous regions were identified in the C. mechowi genome. Eight H. glaber chromosomes are retained in toto in C. mechowi, and 13 produce two or more signals in this species. The most striking difference in the karyotypes of the two taxa concerns their sex chromosomes. The H. glaber painting probes identified a complex series of translocations that involved the fractionation of four autosomes and the subsequent translocation of segments to the sex chromosomes and to autosomal partners in the C. mechowi genome. An intercalary heterochromatic block (IHB) was detected in sex chromosomes of C. mechowi at the boundary with the translocated autosomal segment. We discuss the likely sequence of evolutionary events that has led to the contemporary composition of the C. mechowi sex chromosomes, and consider these in the light of prevailing views on the genesis of sex chromosomes in mammals.
Collapse
Affiliation(s)
- J L Deuve
- Evolutionary Genetics Group, Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
| | | | | | | | | | | | | |
Collapse
|
46
|
Castiglia R, Garagna S, Merico V, Oguge N, Corti M. Cytogenetics of a new cytotype of African Mus (subgenus Nannomys) minutoides (Rodentia, Muridae) from Kenya: C- and G- banding and distribution of (TTAGGG)n telomeric sequences. Chromosome Res 2006; 14:587-94. [PMID: 16823620 DOI: 10.1007/s10577-006-1054-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Revised: 03/23/2006] [Accepted: 03/23/2006] [Indexed: 12/01/2022]
Abstract
We present the results of a cytogenetic study on Mus (Nannomys) minutoides from Kenya by means of C- and G- banding and in-situ fluorescence hybridization (FISH) to localize the telomeric sequences. The karyotype is characterized by the occurrence of several Rb chromosomes Rb(1.X), Rb(1.Y). Rb(2.17), Rb(3.13), Rb(4.10), Rb(5.11), Rb(6.7), Rb(8.12), not previously described for this species. This finding suggests a high level of chromosomal diversification, which means it is possible to consider this cytotype as a new, well-differentiated, chromosomal lineage within the subgenus. The C-banding of the metaphases illustrated conspicuous blocks of centromeric heterochromatin at the paracentromeric regions of all telocentric chromosomes. Centromeric heterochromatin is not visible on all biarmed chromosomes. Following hybridization with telomeric probes, bright interstitial telomeric sequence (ITS) fluorescence signals are evident at the pericentromeric area of all Rb chromosomes, with the exception of Rb(2.17). Considering the localization of the C-positive heterochromatin and of the telomeric sequences, the events leading to the Kenyan cytotype from an all-telocentric condition probably included two steps: first, fusion without loss of heterochromatin and pericentromeric telomeric sequences; second, the reduction of the C-positive satellite DNA followed by the amplification of telomeric sequences in the C-negative paracentromeric region of Rb chromosomes. The presence of a single Rb(2.17) without ITS indicates possible variations of this mechanism.
Collapse
Affiliation(s)
- Riccardo Castiglia
- Dipartimento di Biologia Animale e dell'Uomo, Università di Roma La Sapienza, via A. Borelli 50, 00161, Roma, Italy.
| | | | | | | | | |
Collapse
|
47
|
Scott LA, Kuroiwa A, Matsuda Y, Wichman HA. X accumulation of LINE-1 retrotransposons in Tokudaia osimensis, a spiny rat with the karyotype XO. Cytogenet Genome Res 2006; 112:261-9. [PMID: 16484782 DOI: 10.1159/000089880] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Accepted: 07/25/2005] [Indexed: 01/02/2023] Open
Abstract
The observation that LINE-1 transposable elements are enriched on the X in comparison to the autosomes led to the hypothesis that LINE-1s play a role in X chromosome inactivation. If this hypothesis is correct, loss of LINE-1 activity would be expected to result in species extinction or in an alternate pathway of dosage compensation. One such alternative pathway would be to evolve a karyotype that does not require dosage compensation between the sexes. Two of the three extant species of the Ryukyu spiny rat Tokudaia have such a karyotype; both males and females are XO. We asked whether this karyotype arose due to loss of LINE-1 activity and thus the loss of a putative component in the X inactivation pathway. Although XO Tokudaia has no need for dosage compensation, LINE-1s have been recently active in Tokudaia osimensis and show higher density on the lone X than on the autosomes.
Collapse
Affiliation(s)
- L A Scott
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USA
| | | | | | | |
Collapse
|
48
|
Abstract
Mammalian X chromosome inactivation is one of the most striking examples of epigenetic gene regulation. Early in development one of the pair of approximately 160-Mb X chromosomes is chosen to be silenced, and this silencing is then stably inherited through subsequent somatic cell divisions. Recent advances have revealed many of the chromatin changes that underlie this stable silencing of an entire chromosome. The key initiator of these changes is a functional RNA, XIST, which is transcribed from, and associates with, the inactive X chromosome, although the mechanism of association with the inactive X and recruitment of facultative heterochromatin remain to be elucidated. This review describes the unique evolutionary history and resulting genomic structure of the X chromosome as well as the current understanding of the factors and events involved in silencing an X chromosome in mammals.
Collapse
Affiliation(s)
- Jennifer C Chow
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
| | | | | | | |
Collapse
|
49
|
Yoshido A, Marec F, Sahara K. Resolution of sex chromosome constitution by genomic in situ hybridization and fluorescence in situ hybridization with (TTAGG) n telomeric probe in some species of Lepidoptera. Chromosoma 2005; 114:193-202. [PMID: 16021495 DOI: 10.1007/s00412-005-0013-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Revised: 06/15/2005] [Accepted: 06/21/2005] [Indexed: 11/28/2022]
Abstract
We have developed a simple method to resolve the sex chromosome constitution in females of Lepidoptera by using a combination of genomic in situ hybridization (GISH) and fluorescence in situ hybridization with (TTAGG)( n ) telomeric probe (telomere-FISH). In pachytene configurations of sex chromosomes, GISH differentiated W heterochromatin and telomere-FISH detected the chromosome ends. With this method we showed that Antheraea yamamai has a standard system with a fully differentiated W-Z sex chromosome pair. In Orgyia antiqua, we confirmed the presence of neo-W and neo-Z chromosomes, which most probably originated by fusion of the ancestral W and Z with an autosome pair. In contrast to earlier data, Orgyia thyellina females displayed a neo-ZW(1)W(2) sex chromosome constitution. A neo-WZ(1)Z(2) trivalent was found in females of Samia cynthia subsp. indet., originating from a population in Nagano, Japan. Whereas another subspecies collected in Sapporo, Japan, and determined as S. cynthia walkeri, showed a neo-W/neo-Z bivalent similar to O. antiqua, and the subspecies S. cynthia ricini showed a Z univalent (a Z/ZZ system). The combination of GISH and telomere-FISH enabled us to acquire not only reliable information about sex chromosome constitution but also an insight into sex chromosome evolution in Lepidoptera.
Collapse
Affiliation(s)
- Atsuo Yoshido
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University N9, W9, Kita-ku, Sapporo 060-8589, Japan
| | | | | |
Collapse
|
50
|
Veyrunes F, Catalan J, Sicard B, Robinson TJ, Duplantier JM, Granjon L, Dobigny G, Britton-Davidian J. Autosome and sex chromosome diversity among the African pygmy mice, subgenus Nannomys (Murinae; Mus). Chromosome Res 2005; 12:369-82. [PMID: 15241016 DOI: 10.1023/b:chro.0000034098.09885.e6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The African pygmy mice, subgenus Nannomys, constitute the most speciose lineage of the genus Mus with 19 recognized species. Although morphologically very similar, they exhibit considerable chromosomal diversity which is here confirmed and extended by the G-banding analysis of 65 mice from West and South Africa. On the basis of their karyotype and distribution area, the specimens were assigned to at least five species. Extensive differentiation both within and between species was observed that involved almost exclusively Robertsonian translocations, 23 of which are newly described. Two of the rearrangements were sex chromosome-autosome translocations, associated in some cases with partial deletions of the X or Y chromosomes. Several authors have predicted that the highly deleterious effect of this rearrangement would be reduced if the sex and autosomal segments were insulated by a block of centromeric heterochromatin. The C-banding analyses performed showed that among the species carrying X-autosome translocations, one followed the expected pattern, while the other did not. In this case, functional isolation of the sex and autosome compartments must involve other repetitive sequences or genomic traits that require further molecular characterization. Such studies will provide insight into the causes and consequences of the high diversity of sex chromosome rearrangements in this subgenus.
Collapse
Affiliation(s)
- Frédéric Veyrunes
- Institut des Sciences de l'Evolution (UMR5554), Génétique & Environnement, Université Montpellier II, Montpellier, France.
| | | | | | | | | | | | | | | |
Collapse
|