|
1
|
Nath S, Welch LA, Flanagan MK, White MA. Meiotic pairing and double-strand break formation along the heteromorphic threespine stickleback sex chromosomes. Chromosome Res 2022; 30:429-442. [PMID: 35635635 DOI: 10.1007/s10577-022-09699-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 01/25/2023]
Abstract
Double-strand break repair during meiosis is normally achieved using the homologous chromosome as a repair template. Heteromorphic sex chromosomes share little sequence homology, presenting unique challenges to the repair of double-strand breaks. Our understanding of how heteromorphic sex chromosomes behave during meiosis has been focused on ancient sex chromosomes, where the X and Y differ markedly in overall structure and gene content. It remains unclear how more recently evolved sex chromosomes that share considerably more sequence homology with one another pair and form double-strand breaks. One possibility is barriers to pairing evolve rapidly. Alternatively, recently evolved sex chromosomes may exhibit pairing and double-strand break repair that more closely resembles that of their autosomal ancestors. Here, we use the recently evolved X and Y chromosomes of the threespine stickleback fish (Gasterosteus aculeatus) to study patterns of pairing and double-stranded break formation using molecular cytogenetics. We found that the sex chromosomes of threespine stickleback fish did not pair exclusively in the pseudoautosomal region. Instead, the chromosomes fully paired in a non-homologous fashion. To achieve this, the X chromosome underwent synaptic adjustment during pachytene to match the axis length of the Y chromosome. Double-strand break formation and repair rate also matched that of the autosomes. Our results highlight that recently evolved sex chromosomes exhibit meiotic behavior that is reminiscent of autosomes and argues for further work to identify the homologous templates that are used to repair double-strand breaks on the X and Y chromosomes.
Collapse
Affiliation(s)
- Shivangi Nath
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Lucille A Welch
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Mary K Flanagan
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA
| | - Michael A White
- Department of Genetics, University of Georgia, 120 Green St, Athens, GA, 30602, USA.
| |
Collapse
|
|
2
|
Gil-Fernández A, Ribagorda M, Martín-Ruiz M, López-Jiménez P, Laguna T, Gómez R, Parra MT, Viera A, Veyrunes F, Page J. Meiotic Behavior of Achiasmate Sex Chromosomes in the African Pygmy Mouse Mus mattheyi Offers New Insights into the Evolution of Sex Chromosome Pairing and Segregation in Mammals. Genes (Basel) 2021; 12:1434. [PMID: 34573416 PMCID: PMC8471055 DOI: 10.3390/genes12091434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
X and Y chromosomes in mammals are different in size and gene content due to an evolutionary process of differentiation and degeneration of the Y chromosome. Nevertheless, these chromosomes usually share a small region of homology, the pseudoautosomal region (PAR), which allows them to perform a partial synapsis and undergo reciprocal recombination during meiosis, which ensures their segregation. However, in some mammalian species the PAR has been lost, which challenges the pairing and segregation of sex chromosomes in meiosis. The African pygmy mouse Mus mattheyi shows completely differentiated sex chromosomes, representing an uncommon evolutionary situation among mouse species. We have performed a detailed analysis of the location of proteins involved in synaptonemal complex assembly (SYCP3), recombination (RPA, RAD51 and MLH1) and sex chromosome inactivation (γH2AX) in this species. We found that neither synapsis nor chiasmata are found between sex chromosomes and their pairing is notably delayed compared to autosomes. Interestingly, the Y chromosome only incorporates RPA and RAD51 in a reduced fraction of spermatocytes, indicating a particular DNA repair dynamic on this chromosome. The analysis of segregation revealed that sex chromosomes are associated until metaphase-I just by a chromatin contact. Unexpectedly, both sex chromosomes remain labelled with γH2AX during first meiotic division. This chromatin contact is probably enough to maintain sex chromosome association up to anaphase-I and, therefore, could be relevant to ensure their reductional segregation. The results presented suggest that the regulation of both DNA repair and epigenetic modifications in the sex chromosomes can have a great impact on the divergence of sex chromosomes and their proper transmission, widening our understanding on the relationship between meiosis and the evolution of sex chromosomes in mammals.
Collapse
Affiliation(s)
- Ana Gil-Fernández
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Marta Ribagorda
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Marta Martín-Ruiz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Pablo López-Jiménez
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Tamara Laguna
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Rocío Gómez
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - María Teresa Parra
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Alberto Viera
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| | - Frederic Veyrunes
- Institut des Sciences de l’Evolution, ISEM UMR 5554 (CNRS/Université Montpellier/IRD/EPHE), 34090 Montpellier, France;
| | - Jesús Page
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.G.-F.); (M.R.); (M.M.-R.); (P.L.-J.); (T.L.); (R.G.); (M.T.P.); (A.V.)
| |
Collapse
|