We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
A Comparison of Selective Pressures in Plant X-Linked and Autosomal Genes.
- Authors
Krasovec, Marc; Nevado, Bruno; Filatov, Dmitry A.
- Abstract
Selection is expected to work differently in autosomal and X-linked genes because of their ploidy difference and the exposure of recessive X-linked mutations to haploid selection in males. However, it is not clear whether these expectations apply to recently evolved sex chromosomes, where many genes retain functional X- and Y-linked gametologs. We took advantage of the recently evolved sex chromosomes in the plant <italic>Silene latifolia</italic> and its closely related species to compare the selective pressures between hemizygous and non-hemizygous X-linked genes as well as between X-linked genes and autosomal genes. Our analysis, based on over 1000 genes, demonstrated that, similar to animals, X-linked genes in <italic>Silene</italic> evolve significantly faster than autosomal genes—the so-called faster-X effect. Contrary to expectations, faster-X divergence was detectable only for non-hemizygous X-linked genes. Our phylogeny-based analyses of selection revealed no evidence for faster adaptation in X-linked genes compared to autosomal genes. On the other hand, partial relaxation of purifying selection was apparent on the X-chromosome compared to the autosomes, consistent with a smaller genetic diversity in <italic>S. latifolia</italic> X-linked genes (πx = 0.016; πaut = 0.023). Thus, the faster-X divergence in <italic>S. latifolia</italic> appears to be a consequence of the smaller effective population size rather than of a faster adaptive evolution on the X-chromosome. We argue that this may be a general feature of “young” sex chromosomes, where the majority of X-linked genes are not hemizygous, preventing haploid selection in heterogametic sex.
- Subjects
SELECTIVE inhibition (Chemistry); PLOIDY; PHYLOGENY; SEX chromosomes; X chromosome
- Publication
Genes, 2018, Vol 9, Issue 5, p234
- ISSN
2073-4425
- Publication type
Article
- DOI
10.3390/genes9050234