y chromosome
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eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Ching-Ho Chang ◽  
Lauren E Gregory ◽  
Kathleen E Gordon ◽  
Colin D Meiklejohn ◽  
Amanda M Larracuente

Y chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposons, and satellite DNA. Sexual antagonism and a loss of recombination play major roles in the degeneration of young Y chromosomes. However, the processes shaping the evolution of mature, already degenerated Y chromosomes are less well-understood. Because Y chromosomes evolve rapidly, comparisons between closely related species are particularly useful. We generated de novo long read assemblies complemented with cytological validation to reveal Y chromosome organization in three closely related species of the Drosophila simulans complex, which diverged only 250,000 years ago and share >98% sequence identity. We find these Y chromosomes are divergent in their organization and repetitive DNA composition and discover new Y-linked gene families whose evolution is driven by both positive selection and gene conversion. These Y chromosomes are also enriched for large deletions, suggesting that the repair of double-strand breaks on Y chromosomes may be biased toward microhomology-mediated end joining over canonical non-homologous end-joining. We propose that this repair mechanism contributes to the convergent evolution of Y chromosome organization across organisms.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaopeng Hu ◽  
Hu Wang ◽  
Geng. G. Tian ◽  
Changliang Hou ◽  
Bo Xu ◽  
...  

Abstract Background During male meiosis, the Y chromosome can form perfect pairing with the X chromosome. However, it is unclear whether mammalian Female germline stem cells (FGSCs) without a Y chromosome can transdifferentiate into functional haploid spermatid-like cells (SLCs). Results We found that spermatogenesis was restarted by transplanting FGSCs into Kitw/wv mutant testes. Complete meiosis and formation of SLCs was induced in vitro by testicular cells of Kitw/wv mutant mice, cytokines and retinoic acid. Healthy offspring were produced by sperm and SLCs derived from the in vivo and in vitro transdifferentiation of FGSCs, respectively. Furthermore, high-throughput chromosome conformation capture sequencing(Hi-C-seq) and “bivalent” (H3K4me3-H3K27me3) micro chromatin immunoprecipitation sequencing (μChIP-seq) experiments showed that stimulated by retinoic acid gene 8 (STRA8)/protamine 1 (PRM1)-positive transdifferentiated germ cells (tGCs) and male germ cells (mGCs) display similar chromatin dynamics and chromatin condensation during in vitro spermatogenesis. Conclusion This study demonstrates that sperm can be produced from FGSCs without a Y chromosome. This suggests a strategy for dairy cattle breeding to produce only female offspring with a high-quality genetic background.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Raheleh Heydari ◽  
Zohreh Jangravi ◽  
Samaneh Maleknia ◽  
Mehrshad Seresht-Ahmadi ◽  
Zahra Bahari ◽  
...  

AbstractAlthough sex hormones play a key role in sex differences in susceptibility, severity, outcomes, and response to therapy of different diseases, sex chromosomes are also increasingly recognized as an important factor. Studies demonstrated that the Y chromosome is not a ‘genetic wasteland’ and can be a useful genetic marker for interpreting various male-specific physiological and pathophysiological characteristics. Y chromosome harbors male‑specific genes, which either solely or in cooperation with their X-counterpart, and independent or in conjunction with sex hormones have a considerable impact on basic physiology and disease mechanisms in most or all tissues development. Furthermore, loss of Y chromosome and/or aberrant expression of Y chromosome genes cause sex differences in disease mechanisms. With the launch of the human proteome project (HPP), the association of Y chromosome proteins with pathological conditions has been increasingly explored. In this review, the involvement of Y chromosome genes in male-specific diseases such as prostate cancer and the cases that are more prevalent in men, such as cardiovascular disease, neurological disease, and cancers, has been highlighted. Understanding the molecular mechanisms underlying Y chromosome-related diseases can have a significant impact on the prevention, diagnosis, and treatment of diseases.


2022 ◽  
Vol 34 (2) ◽  
pp. 268
Author(s):  
A. Velázquez-Roque ◽  
H. Álvarez-Gallardo ◽  
M. Kjelland ◽  
M. Pérez-Martínez ◽  
F. Villaseñor-González ◽  
...  

2022 ◽  
Vol 34 (2) ◽  
pp. 250
Author(s):  
H. Álvarez-Gallardo ◽  
M. Kjelland ◽  
M. Pérez-Martínez ◽  
A. Velázquez-Roque ◽  
F. Villaseñor-González ◽  
...  

Author(s):  
P. Ramajayan ◽  
S.N. Sivaselvam ◽  
S.M.K. Karthickeyan ◽  
A. Gopinathan ◽  
S. Poobitha

Background: Molecular markers based approaches are essential to select fertile bulls for frozen semen production at an early age. The present investigation was undertaken to perform the molecular characterization and identify single nucleotide polymorphisms (SNP) in Y-chromosome specific DDX3Y gene in Murrah buffalo bulls. Methods: The genomic DNA isolated from the blood samples of 70 Murrah buffalo bulls, covering bulls with normal seminal traits and poor production performance (poor semen quality, freezability, libido), were subjected to PCR amplification. The sequences of DDX3Y gene were analyzed for single nucleotide polymorphism using the seqman module of DNASTAR LASERGENE software. The single nucleotide variations in the sequences with reference to the Bos taurus sequence were determined using Clustal W. The phylogenetic tree and genetic distance were constructed using the MegAlign module. Result: The analysis of sequences revealed that the exons and their adjacent intronic regions of the DDX3Y gene are monomorphic in nature without any variations indicating that the sequences are highly conserved in the studied population of Murrah buffalo bulls. However, a considerable number of single nucleotide variations were observed in the sequences of Murrah buffalo compared with Bos taurus sequences. Furthermore, the phylogenetic tree analysis revealed less divergence and close genetic association between the sequences of Murrah buffalo and other species in the bovinae family than the caprinea species. Further studies on DDX3Y gene in a more extensive and diverse population of Murrah buffalo bulls distributed in different regions could aid to discover substantial SNPs.


2021 ◽  
Vol 36 (4) ◽  
pp. 239-246
Author(s):  
So-Yeon Jo ◽  
Yong Hwangbo ◽  
Sang-Hee Lee ◽  
Hee-Tae Cheong ◽  
Dong-Ku Kim ◽  
...  

2021 ◽  
Vol 18 (4) ◽  
pp. 817-822
Author(s):  
Arshad Ayoub Bhatti ◽  
Nidhi Slathia ◽  
Manvi K

Chromosomal studies and manual karyotyping are the aged techniques for determining the identity of a species on evolutionary scale; however, these techniques are simple, reliable and inexpensive to authenticate the existence of a particular species. In the present work, the chromosome complement and meiotic processes of a predatory bombardier beetle Pherosophus catoirai were investigated. This species presented 2n=35 as diploid chromosome number and the chromosomal formula was found to be 12m+8sm+12st+X0. Sex mechanism was X0 type with metacentric X chromosome. Y chromosome was absent in this species. Karyotype revealed small chromosomes except X chromosome which is found to be largest in the spermatogonial metaphase stage. Meiotic stages were pachytene, diplotene, diakinesis and metaphase-I. Present study may find importance to analyse evolution of chromosomes in order Coleoptera particularly in family Carabidae.


2021 ◽  
Vol 13 (2) ◽  
pp. 32-37
Author(s):  
Hawraa Al-Mohamadawi ◽  
Asaad Y. Ayied

The origin of animals is usually determined by their paternal genotypes of the genes on the Y chromosome. In addition to the genes and their polymorphisms in the genome of mitochondria that are inherited through dams. In view of the lack of studies focusing on the genes of the Y chromosome in the world and their absence in Iraq. The aim of the present study was to identify the multiple genetic polymorphisms of the SRYM18 gene in the Arabi and Awassi sheep raised in Iraq. The study was conducted in the Genetic Engineering Laboratories - College of Agriculture, University of Basra, as well as in the Basra Genome Laboratory. The amplification of the SRYM18 gene showed genetic polymorphisms and gave a gene segment of (103-880) bp. The number of alleles of the SRYm18 gene was 13 alleles in the Arabi and 16 alleles in the Awassi breeds. The equilibrium test showed that the two breeds were under equilibrium. The two breeds were identical with nine alleles, while the number of special alleles for the Arabi breed was two, while the Awassi breed was distinguished by five. The number of rare alleles reached 20, of which seven were of the Arabi breed, and 13 of them were of the Awassi breed. Mean expected heterozygosity was 0.6386 with nonsignificant Fis for Arabi breed (0.1541) but significant for Awassi breed (0.2213). Mean neutrality was close to lower bound (0.1721) and (0.1270) for Arabi and Awassi breeds respectively


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