1
|
Williams S, Hawley RS. From conservation to adaptation: understanding the synaptonemal complex's evolutionary dynamics. Curr Opin Genet Dev 2025; 93:102349. [PMID: 40250163 DOI: 10.1016/j.gde.2025.102349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2025] [Revised: 03/25/2025] [Accepted: 03/30/2025] [Indexed: 04/20/2025]
Abstract
The synaptonemal complex (SC) is structurally conserved across eukaryotes and is essential for a proper progression of meiosis. Despite this conservation, SC protein sequences diverge drastically. In this review, we explore findings on SC protein evolution, highlighting key differences and commonalities among lineages like the Caenorhabditis and the Drosophila genera. We further explore known cases where the SC and its proteins adopt novel functional roles and discuss why knowledge of these cases could be important for the study of canonical SC biology. The existing studies demonstrate that work on the evolutionary biology of SC proteins and functional studies in more diverse meiotic research organisms should play a major role in aiding our understanding of SC structure and functions.
Collapse
Affiliation(s)
- Stefanie Williams
- Stowers Institute for Medical Research, Kansas City, Missouri, United States.
| | - Robin Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri, United States
| |
Collapse
|
2
|
Wang D, Xiang Y, Zhu Z, Liu J, Wang Y, Xu Z, Chen S, Dai C, Feng J, Chen J, Ma Q, Yang P. Cytological Effects of Cadmium Poisoning and the Protective Effect of Quercetin: A Mechanism Exploration based on the Testicular Lamina Propria. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2025; 31:ozae103. [PMID: 39405407 DOI: 10.1093/mam/ozae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 08/19/2024] [Accepted: 09/15/2024] [Indexed: 02/26/2025]
Abstract
This comprehensive study delved into the detrimental effects of cadmium (Cd), a toxic heavy metal, on the testicular lamina propria (LP), a key player in spermatogenesis, and the maintenance of testicular stem cell niches. Utilizing transmission electron microscopy, immunohistochemistry, and double-labeling immunofluorescence, the research characterized the structural and cellular components of mouse testicular LP under Cd exposure and investigated the protective effects of quercetin. The findings illustrated that Cd exposure results in significant morphological and cellular modifications within the LP, including the apoptosis of peritubular myoid cells, an upsurge in CD34+ stromal cells displaying anti-apoptotic behaviors, and an excessive production of collagen Type I fibers and extracellular matrix. Remarkably, quercetin effectively counteracted these adverse changes by reversing apoptosis, reducing the proliferation of CD34+ stromal cells, and addressing fibrosis markers, thereby mitigating the cellular damage induced by Cd. This study not only highlighted the critical impact of apoptosis and fibrosis in Cd-related testicular damage but also elucidated the protective mechanism of quercetin, laying the groundwork for future clinical applications in addressing testicular damage from heavy metal poisoning through cellular therapeutics and pharmacological interventions.
Collapse
Affiliation(s)
- Dian Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Yi Xiang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Zhaoxuan Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Jiyue Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Yisheng Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Zeyu Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Si Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Chunyuan Dai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Jiasen Feng
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| | - Jie Chen
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China
| | - Qianhui Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences-University of Chinese Academy of Sciences, No. 320 Yueyang Road, Shanghai 200031, China
| | - Ping Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Weigang No. 1, Nanjing 210095, China
| |
Collapse
|
3
|
Chen Y, Lin X, Dai J, Bai Y, Liu F, Luo D. Deletion of ddx4 Ovary-Specific Transcript Causes Dysfunction of Meiosis and Derepress of DNA Transposons in Zebrafish Ovaries. BIOLOGY 2024; 13:1055. [PMID: 39765722 PMCID: PMC11673608 DOI: 10.3390/biology13121055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2024] [Revised: 12/06/2024] [Accepted: 12/09/2024] [Indexed: 01/11/2025]
Abstract
Alternative splicing of ddx4 (DEAD-box helicase 4), a key germline marker gene, has been reported to generate sex-specific transcripts in zebrafish gonads. The biological functions and regulatory mechanisms of the ddx4 ovary-specific transcript (ddx4-L) during oogenesis remain unclear. In this study, we found that ddx4-L mutants, in which ddx4-L was specifically deleted, had enlarged ovaries but laid fewer eggs, along with having a lower fertilization rate compared to WT controls. RNA-seq analysis was performed to detect the changes in gene expression between WT and ddx4-L mutant ovaries. A total of 524 upregulated and 610 downregulated DEGs were identified. GO and GSEA enrichment analyses showed that genes involved in fertilization and reproduction biological processes were significantly downregulated. More specifically, we observed a remarkable reduction in Sycp1, a core component of synaptonemal complex, in ddx4-L mutant ovaries at both the mRNA and protein levels. In addition, the expressions of transposon elements, as well as the events of alternative splicing, alternative polyadenylation, and RNA editing, were analyzed based on the RNA-seq data. We found that the deletion of ddx4-L resulted in derepression of DNA transposons in zebrafish ovaries, possibly causing genome instability. In conclusion, our work demonstrates that the ovary-specific ddx4 transcript plays important roles in oocyte meiosis and DNA transposon repression, which extends our understanding of the biological functions and regulatory mechanisms of sex-specific alternative splicing in zebrafish oogenesis and reproduction.
Collapse
Affiliation(s)
- Yuanyuan Chen
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Lin
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Dai
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- Joint National Laboratory for Antibody Drug Engineering, School of Medicine, Henan University, Kaifeng 475004, China
| | - Yifan Bai
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Liu
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daji Luo
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (X.L.)
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| |
Collapse
|
4
|
Jiang N, Li Y, Yin L, Yuan S, Wang F. The Intricate Functional Networks of Pre-mRNA Alternative Splicing in Mammalian Spermatogenesis. Int J Mol Sci 2024; 25:12074. [PMID: 39596142 PMCID: PMC11594017 DOI: 10.3390/ijms252212074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2024] [Revised: 11/08/2024] [Accepted: 11/08/2024] [Indexed: 11/28/2024] Open
Abstract
Spermatogenesis is a highly coordinated process that requires the precise expression of specific subsets of genes in different types of germ cells, controlled both temporally and spatially. Among these genes, those that can exert an indispensable influence in spermatogenesis via participating in alternative splicing make up the overwhelming majority. mRNA alternative-splicing (AS) events can generate various isoforms with distinct functions from a single DNA sequence, based on specific AS codes. In addition to enhancing the finite diversity of the genome, AS can also regulate the transcription and translation of certain genes by directly binding to their cis-elements or by recruiting trans-elements that interact with consensus motifs. The testis, being one of the most complex tissue transcriptomes, undergoes unparalleled transcriptional and translational activity, supporting the dramatic and dynamic transitions that occur during spermatogenesis. Consequently, AS plays a vital role in producing an extensive array of transcripts and coordinating significant changes throughout this process. In this review, we summarize the intricate functional network of alternative splicing in spermatogenesis based on the integration of current research findings.
Collapse
Affiliation(s)
| | | | | | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (N.J.); (Y.L.); (L.Y.)
| | - Fengli Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; (N.J.); (Y.L.); (L.Y.)
| |
Collapse
|
5
|
Rodriguez-Reza CM, Sato-Carlton A, Carlton PM. Length-sensitive partitioning of Caenorhabditis elegans meiotic chromosomes responds to proximity and number of crossover sites. Curr Biol 2024; 34:4998-5016.e6. [PMID: 39395418 DOI: 10.1016/j.cub.2024.09.034] [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: 05/21/2024] [Revised: 08/16/2024] [Accepted: 09/12/2024] [Indexed: 10/14/2024]
Abstract
Sensing and control of size are critical for cellular function and survival. A striking example of size sensing occurs during meiosis in the nematode Caenorhabditis elegans. C. elegans chromosomes compare the lengths of the two chromosome "arms" demarcated by the position of their single off-center crossover, and they differentially modify these arms to ensure that sister chromatid cohesion is lost specifically on the shorter arm in the first meiotic division, while the longer arm maintains cohesion until the second division. While many of the downstream steps leading to cohesion loss have been characterized, the length-sensing process itself remains poorly understood. Here, we have used cytological visualization of short and long chromosome arms, combined with quantitative microscopy, live imaging, and simulations, to investigate the principles underlying length-sensitive chromosome partitioning. By quantitatively analyzing short-arm designation patterns on fusion chromosomes carrying multiple crossovers, we develop a model in which a short-arm-determining factor originates at crossover designation sites, diffuses within the synaptonemal complex, and accumulates within crossover-bounded chromosome segments. We demonstrate experimental support for a critical assumption of this model: that crossovers act as boundaries to diffusion within the synaptonemal complex. Further, we develop a discrete simulation based on our results that recapitulates a wide variety of observed partitioning outcomes in both wild-type and previously reported mutants. Our results suggest that the concentration of a diffusible factor is used as a proxy for chromosome length, enabling the correct designation of short and long arms and proper segregation of chromosomes.
Collapse
Affiliation(s)
| | - Aya Sato-Carlton
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Kyoto 606-8501, Japan.
| | - Peter M Carlton
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Kyoto 606-8501, Japan; Radiation Biology Center, Kyoto University, Yoshida-Konoecho, Kyoto 606-8501, Japan.
| |
Collapse
|
6
|
Wang T, Leng D, Cai Z, Chen B, Li J, Kui H, Li D, Li Z. Insights into left-right asymmetric development of chicken ovary at the single-cell level. J Genet Genomics 2024; 51:1265-1277. [PMID: 39147128 DOI: 10.1016/j.jgg.2024.08.002] [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: 04/18/2024] [Revised: 07/29/2024] [Accepted: 08/02/2024] [Indexed: 08/17/2024]
Abstract
Avian ovaries develop asymmetrically apart from prey birds, with only the left ovary growing more towards functional organ. Here, we analyze over 135,000 cells from chick's left and right ovaries at six distinct embryonic developmental stages utilizing single-cell transcriptome sequencing. We delineate gene expression patterns across 15 cell types within these embryo ovaries, revealing side-specific development. The left ovaries exhibit cortex cells, zygotene germ cells, and transcriptional changes unique to the left side. Differential gene expression analysis further identifies specific markers and pathways active in these cell types, highlighting the asymmetry in ovarian development. A fine-scale analysis of the germ cell meiotic transcriptome reveals seven distinct clusters with gene expression patterns specific to various meiotic stages. The study also identifies signaling pathways and intercellular communications, particularly between pre-granulosa and germ cells. Spatial transcriptome analysis shows the asymmetry, demonstrating cortex cells exclusively in the left ovary, modulating neighboring cell types through putative secreted signaling molecules. Overall, this single-cell analysis provides insights into the molecular mechanisms of the asymmetric development of avian ovaries, particularly the significant role of cortex cells in the left ovary.
Collapse
Affiliation(s)
- Tao Wang
- School of Pharmacy, Chengdu University, Chengdu, Sichuan 610106, China
| | - Dong Leng
- School of Pharmacy, Chengdu University, Chengdu, Sichuan 610106, China
| | - Zhongkun Cai
- School of Pharmacy, Chengdu University, Chengdu, Sichuan 610106, China
| | - Binlong Chen
- College of Animal Science, Xichang University, Xichang, Sichuan 615000, China
| | - Jing Li
- School of Agriculture and Life Sciences, Kunming University, Kunming, Yunnan 650214, China
| | - Hua Kui
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Diyan Li
- School of Pharmacy, Chengdu University, Chengdu, Sichuan 610106, China.
| | - Zhuanjian Li
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, Henan 450046, China.
| |
Collapse
|
7
|
Yan Z, Wang P, Yang Q, Gun S. Single-Cell RNA Sequencing Reveals an Atlas of Hezuo Pig Testis Cells. Int J Mol Sci 2024; 25:9786. [PMID: 39337274 PMCID: PMC11431743 DOI: 10.3390/ijms25189786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 08/25/2024] [Accepted: 09/04/2024] [Indexed: 09/30/2024] Open
Abstract
Spermatogenesis is a complex biological process crucial for male reproduction and is characterized by intricate interactions between testicular somatic cells and germ cells. Due to the cellular heterogeneity of the testes, investigating different cell types across developmental stages has been challenging. Single-cell RNA sequencing (scRNA-seq) has emerged as a valuable approach for addressing this limitation. Here, we conducted an unbiased transcriptomic study of spermatogenesis in sexually mature 4-month-old Hezuo pigs using 10× Genomics-based scRNA-seq. A total of 16,082 cells were collected from Hezuo pig testes, including germ cells (spermatogonia (SPG), spermatocytes (SPCs), spermatids (SPTs), and sperm (SP)) and somatic cells (Sertoli cells (SCs), Leydig cells (LCs), myoid cells (MCs), endothelial cells (ECs), and natural killer (NK) cells/macrophages). Pseudo-time analysis revealed that LCs and MCs originated from common progenitors in the Hezuo pig. Functional enrichment analysis indicated that the differentially expressed genes (DEGs) in the different types of testicular germ cells were enriched in the PI3K-AKT, Wnt, HIF-1, and adherens junction signaling pathways, while the DEGs in testicular somatic cells were enriched in ECM-receptor interaction and antigen processing and presentation. Moreover, genes related to spermatogenesis, male gamete generation, sperm part, sperm flagellum, and peptide biosynthesis were expressed throughout spermatogenesis. Using immunohistochemistry, we verified several stage-specific marker genes (such as UCHL1, WT1, SOX9, and ACTA2) for SPG, SCs, and MCs. By exploring the changes in the transcription patterns of various cell types during spermatogenesis, our study provided novel insights into spermatogenesis and testicular cells in the Hezuo pig, thereby laying the foundation for the breeding and preservation of this breed.
Collapse
Affiliation(s)
| | | | - Qiaoli Yang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (Z.Y.); (P.W.)
| | - Shuangbao Gun
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (Z.Y.); (P.W.)
| |
Collapse
|
8
|
Li S, Liu L, Ahmed Z, Wang F, Lei C, Sun F. Identification of Heilongjiang crossbred beef cattle pedigrees and reveals functional genes related to economic traits based on whole-genome SNP data. Front Genet 2024; 15:1435793. [PMID: 39119576 PMCID: PMC11306169 DOI: 10.3389/fgene.2024.1435793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 07/08/2024] [Indexed: 08/10/2024] Open
Abstract
Introduction: To enhance the beef cattle industry, Heilongjiang Province has developed a new Crossbred beef cattle variety through crossbreeding with exotic commercial breeds. This new variety exhibits relatively excellent meat quality, and efficient reproductive performance, catering to market demands. Method: This study employed whole genome resequencing technology to analyze the genetic pedigree and diversity of 19 Heilongjiang Crossbred beef cattle, alongside 59 published genomes from East Asian, Eurasian, and European taurine cattle as controls. In addition, genes related to production traits were also searched by identifying Runs of Homozygosity (ROH) islands and important fragments from ancestors. Results: A total of 14,427,729 biallelic SNPs were discovered, with the majority located in intergenic and intron regions and a small percentage in exon regions, impacting protein function. Population genetic analyses including Principal Component Analysis (PCA), Neighbor-Joining (NJ) tree, and ADMIXTURE identified Angus, Holstein, and Mishima as the main ancestors of Crossbred beef cattle. In genetic diversity analysis, nucleotide diversity, linkage disequilibrium, and inbreeding coefficient analysis reveal that the genetic diversity of Crossbred beef cattle is at a moderate level, and a higher inbreeding coefficient indicates the need for careful breeding management. In addition, some genes related to economic traits are identified through the identification of Runs of Homozygosity (ROH) islands and important fragments from ancestors. Conclusion: This comprehensive genomic characterization supports the targeted improvement of economically important traits in Crossbred beef cattle, facilitating advanced breeding strategies.
Collapse
Affiliation(s)
- Shuang Li
- Key Laboratory of Combining Farming and Animal Husbandry of Ministry of Agriculture, Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin, China
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Li Liu
- Key Laboratory of Combining Farming and Animal Husbandry of Ministry of Agriculture, Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Zulfiqar Ahmed
- Department of Livestock and Poultry Production, Faculty of Veterinary and Animal Sciences, University of Poonch Rawalakot, Azad Kashmir, Pakistan
| | - Fuwen Wang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Chuzhao Lei
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Fang Sun
- Key Laboratory of Combining Farming and Animal Husbandry of Ministry of Agriculture, Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin, China
| |
Collapse
|
9
|
Lampitto M, Barchi M. Recent advances in mechanisms ensuring the pairing, synapsis and segregation of XY chromosomes in mice and humans. Cell Mol Life Sci 2024; 81:194. [PMID: 38653846 PMCID: PMC11039559 DOI: 10.1007/s00018-024-05216-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/04/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Sex chromosome aneuploidies are among the most common variations in human whole chromosome copy numbers, with an estimated prevalence in the general population of 1:400 to 1:1400 live births. Unlike whole-chromosome aneuploidies of autosomes, those of sex chromosomes, such as the 47, XXY aneuploidy that causes Klinefelter Syndrome (KS), often originate from the paternal side, caused by a lack of crossover (CO) formation between the X and Y chromosomes. COs must form between all chromosome pairs to pass meiotic checkpoints and are the product of meiotic recombination that occurs between homologous sequences of parental chromosomes. Recombination between male sex chromosomes is more challenging compared to both autosomes and sex chromosomes in females, as it is restricted within a short region of homology between X and Y, called the pseudo-autosomal region (PAR). However, in normal individuals, CO formation occurs in PAR with a higher frequency than in any other region, indicating the presence of mechanisms that promote the initiation and processing of recombination in each meiotic division. In recent years, research has made great strides in identifying genes and mechanisms that facilitate CO formation in the PAR. Here, we outline the most recent and relevant findings in this field. XY chromosome aneuploidy in humans has broad-reaching effects, contributing significantly also to Turner syndrome, spontaneous abortions, oligospermia, and even infertility. Thus, in the years to come, the identification of genes and mechanisms beyond XY aneuploidy is expected to have an impact on the genetic counseling of a wide number of families and adults affected by these disorders.
Collapse
Affiliation(s)
- Matteo Lampitto
- Section of Anatomy, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Marco Barchi
- Section of Anatomy, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
- Section of Anatomy, Department of Medicine, Saint Camillus International University of Health Sciences, Rome, Italy.
| |
Collapse
|