scholarly journals Evidence that positive selection drives Y-chromosome degeneration in Drosophila miranda

2004 ◽  
Vol 36 (5) ◽  
pp. 518-522 ◽  
Author(s):  
Doris Bachtrog
Keyword(s):  
Positive Selection ◽  
Y Chromosome ◽  
Y Chromosome Degeneration

scholarly journals Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes

2021 ◽  
Author(s):  
Ching-Ho Chang ◽  
Lauren E. Gregory ◽  
Kathleen E. Gordon ◽  
Colin D. Meiklejohn ◽  
Amanda M. Larracuente
Keyword(s):  
Positive Selection ◽  
Y Chromosome ◽  
Related Species ◽  
De Novo ◽  
Gene Families ◽  
Chromosome Organization ◽  
End Joining ◽  
Sexual Antagonism ◽  
Closely Related Species ◽  
Y Chromosomes

AbstractY chromosomes across diverse species convergently evolve a gene-poor, heterochromatic organization enriched for duplicated genes, LTR retrotransposable elements, 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 generally contributes to the convergent evolution of Y chromosome organization.

scholarly journals Current Status of Sex Sorted Semen and its Long Term effect on Population Dynamics and Y-Chromosome Degeneration of the Breed Among Dairy Animals in Jharkhand, India: A Review

2021 ◽  
pp. 34-44
Author(s):  
N. Kumari ◽  
S. Prasad ◽  
A. K. Pandey ◽  
S. Dash ◽  
R. Sinha
Keyword(s):  
Population Dynamics ◽  
Y Chromosome ◽  
Assisted Reproductive Technologies ◽  
Negative Impact ◽  
Research Work ◽  
Reproductive Technologies ◽  
Current Status ◽  
Effective Population ◽  
Female Population ◽  
Y Chromosome Degeneration

Sex Sorted Semen gives the liberty of producing offspring of the desired sex - in farming animals by using it in conjunction with other assisted reproductive technologies such as Artificial Insemination and In-Vitro Fertilization after selecting the healthy sperm and separating into X-Female and Y-male Chromosome bearing populations based on their DNA content. It is an important biotechnological tool to increase the milk production and the profitability of Dairy Industry. Current study deals with the Principle, methods, main method, advantages, disadvantages and the current status of Sex sorted semen in India and Jharkhand. The main emphasis of this study is to draw the attention of Scientific fraternity towards the effect of Sex Sorted Semen on Population dynamics. The Sex Sorted semen increases the deviation of ratio between Male and Female Population from ideal 1:1, thereby decreasing the effective population size Ne and thus slowly reducing the viability and survivability of the population or breed concerned. Further the already depleting Y chromosomes will be reaped off all its genes in long run at a faster rate due to antagonistic selection pressure arising out of Artificial selection via Sex Sorted Semen acting against all the gene of Y chromosome of the breed or population concerned which might disturb many vital genes and the associated functions. The degeneration and extinction of scientists have been predicted long ago. The effect of Sex Sorted semen on Y- chromosome degeneration is yet to be pointed out, calculated and subsequently verified in any of the literatures. SSS is indeed a boon for India as well as Jharkhand. It might be too early to predict about the negative impact of SSS on population dynamics and Y-Chromosome degeneration. Further research work must be done to assess the extent and authencity of above mentioned impact( Predicted  theoretically) by calculation as well as practical field based Experimentation.

scholarly journals The Size and Content of the Sex-Determining Region of the Y Chromosome in Dioecious Mercurialis annua, a Plant with Homomorphic Sex Chromosomes

2018 ◽  
Author(s):  
Paris Veltsos ◽  
Guillaume Cossard ◽  
Emmanuel Beaudoing ◽  
Genséric Beydon ◽  
Camille Roux ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sequence Length ◽  
Bacterial Artificial Chromosomes ◽  
Dioecious Plants ◽  
Artificial Chromosomes ◽  
Males And Females ◽  
Male Specific ◽  
Y Chromosome Degeneration ◽  
Mercurialis Annua

Many dioecious plants have sex chromosomes that are cytologically heteromorphic, but about half of species lack cytological differences between males and females and are thus homomorphic. Very little is known about the size and content of the non-recombining sex-determining region (SDR) in these species. Here, we assess the size and content of the SDR of the diploid dioecious herb Mercurialis annua, which has homomorphic sex chromosomes and shows signatures of mild Y-chromosome degeneration. We used RNAseq to identify new Y-linked markers for M. annua. Twelve of 24 transcripts with male-specific and male-biased expression could only be PCR-amplified from males and are thus Y-linked. We found a further six Y-linked sequences that were present in males but not females using genome capture data from multiple populations. We used the Y-linked sequences to identify and sequence 17 sex-linked bacterial artificial chromosomes (BACs), which form 11 groups of non-overlapping sequence, covering a total sequence length of about 1.5 Mb. Content analysis of this region suggests it is enriched for repeats, has a low gene density and contains few candidate sex-determining genes. The BACs map to a subset of the sex-linked region of the genetic map, which is estimated to be at least 14.5 Mb. This is substantially larger than estimates for other dioecious plants with homomorphic sex chromosomes, especially given the small genome size of M. annua. Our data provide a rare, high-resolution view of the homomorphic Y chromosome of a dioecious plant.

scholarly journals Unique structure and positive selection promote the rapid divergence of Drosophila Y chromosomes

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Ching-Ho Chang ◽  
Lauren E Gregory ◽  
Kathleen E Gordon ◽  
Colin D Meiklejohn ◽  
Amanda M Larracuente
Keyword(s):  
Positive Selection ◽  
Y Chromosome ◽  
Related Species ◽  
De Novo ◽  
Gene Families ◽  
Chromosome Organization ◽  
End Joining ◽  
Sexual Antagonism ◽  
Closely Related Species ◽  
Y Chromosomes

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.

The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes

Zebrafish ◽  
2017 ◽  
Vol 14 (3) ◽  
pp. 244-250 ◽  
Author(s):  
Jéssica Almeida Batista ◽  
Adauto Lima Cardoso ◽  
Susana Suely Rodrigues Milhomem-Paixão ◽  
Jonathan Stuart Ready ◽  
Julio Cesar Pieczarka ◽  
...  
Keyword(s):  
Y Chromosome ◽  
First Case ◽  
Y Chromosome Degeneration

scholarly journals Temporal Orders and Y Chromosome Futures: Of Mice, Monkeys, and Men

2019 ◽  
Vol 5 (1) ◽  
pp. 1-18
Author(s):  
Sam Taylor-Alexander ◽  
Sharyn Davies
Keyword(s):  
Molecular Biology ◽  
Y Chromosome ◽  
Human Evolution ◽  
Evolutionary Theories ◽  
The Future ◽  
Crisis Of Masculinity ◽  
Y Chromosome Degeneration

We bring together conceptual readings of time and temporality to discuss evolutionary theories of Y chromosome degeneration as they are spoken about in scientific and popular forums. In doing so, we suggest that debates over Y chromosome degeneration involve a form of abduction – tacking back and forth between different pasts, presents, futures – that frames templates for producing and securing sexed and gendered presents. Here we are using ‘sexed’ as a way of talking about physical bodies and ‘gendered’ as social ways of constructing those sexed bodies. We suggest that arguments over Y chromosome degeneration are as important for current debates surrounding sex, gender, science, molecular biology and a “crisis of masculinity” as they are for (ascertaining) the future of human evolution.

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