Reduced adaptation of a non-recombining neo-Y chromosome

@article{Bachtrog2002ReducedAO,
  title={Reduced adaptation of a non-recombining neo-Y chromosome},
  author={Doris Bachtrog and Brian Charlesworth},
  journal={Nature},
  year={2002},
  volume={416},
  pages={323-326}
}
Sex chromosomes are generally believed to have descended from a pair of homologous autosomes. Suppression of recombination between the ancestral sex chromosomes led to the genetic degeneration of the Y chromosome. In response, the X chromosome may become dosage-compensated. Most proposed mechanisms for the degeneration of Y chromosomes involve the rapid fixation of deleterious mutations on the Y. Alternatively, Y-chromosome degeneration might be a response to a slower rate of adaptive evolution… 
Sex chromosome evolution: molecular aspects of Y-chromosome degeneration in Drosophila.
TLDR
Comparison of four large genomic regions located on the neo-sex chromosomes that contain a total of 12 homologous genes finds that both 5'- and 3'-flanking regions of genes and intron sequences are less constrained on the Nazi-era Y-chromosome compared to its neo-X homolog, which shows surprisingly uniform signs of degeneration.
Protein evolution and codon usage bias on the neo-sex chromosomes of Drosophila miranda.
TLDR
Comparisons of patterns of molecular evolution of 18 protein-coding genes located on the recombining neo-X and their homologs on the nonrecombined neo-Y chromosome suggest that there has been little or no selection maintaining codon bias in the D. miranda lineage.
Genomic degradation of a young Y chromosome in Drosophila miranda
TLDR
Patterns of genome evolution in D. miranda demonstrate that degeneration of a recently formed Y chromosome can proceed very rapidly, by both an accumulation of repetitive DNA and degenerating of protein-coding genes, support a random model of Y inactivation.
Ancient Male Recombination Shaped Genetic Diversity of Neo-Y Chromosome in Drosophila albomicans.
TLDR
This work elucidated the evolutionary scenario of the neo-Y chromosome of D. albomicans having high genetic diversity without assuming selective force, i.e., it originated from a single chromosomal fusion event, experienced meiotic recombination during the initial stage of evolution and diverged from neo-X chromosome by the suppression of recombination.
The Evolutionary Tempo of Sex Chromosome Degradation in Carica papaya
TLDR
A pattern of gene decay on the X-specific region of the Y chromosome may be explained by relaxed purifying selection and widespread genetic hitchhiking due to its pericentromeric location.
Adaptation shapes patterns of genome evolution on sexual and asexual chromosomes in Drosophila
TLDR
The limits to natural selection in an asexual genome are illustrated by comparing patterns of genome evolution in a 40-kb gene-rich region on homologous neo-sex chromosomes of Drosophila miranda.
Accelerated Adaptive Evolution on a Newly Formed X Chromosome
TLDR
Newly formed X chromosomes are not passive players in the evolutionary process of sex chromosome differentiation, but respond adaptively to both their sex-biased transmission and to Y chromosome degeneration, possibly through demasculinization of their gene content and the evolution of dosage compensation.
Expression Profile of a Degenerating Neo-Y Chromosome in Drosophila
Sequence differentiation associated with an inversion on the neo-X chromosome of Drosophila americana.
TLDR
A nucleotide site defining a common haplotype in bib is shown to be associated with a paracentric inversion on the neo-X chromosome, which is consistent with the inversion acting as a recombination modifier that suppresses exchange between these neo-sex chromosomes, as predicted by models of sex chromosome evolution.
Neo-sex chromosomes in the black muntjac recapitulate incipient evolution of mammalian sex chromosomes
TLDR
It is reported for the first time that regulatory mutations were probably able to accelerate the degeneration process of Y and contribute to further evolution of dosage compensation and complex patterns of expression divergence between neo-Y and neo-X alleles.
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