A comparison of selective pressures in plant X-linked and autosomal genes
<p>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...
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| 格式: | Journal article |
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MDPI
2018
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| _version_ | 1826273027088711680 |
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| author | Krasovec, M Nevado, B Filatov, D |
| author_facet | Krasovec, M Nevado, B Filatov, D |
| author_sort | Krasovec, M |
| collection | OXFORD |
| description | <p>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 <i>Silene latifolia</i> 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 <i>Silene</i> 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 <i>S. latifolia</i> X-linked genes (π<sub>x</sub> = 0.016; π<sub>aut</sub> = 0.023). Thus, the faster-X divergence in <i>S. latifolia</i> 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.</p> |
| first_indexed | 2024-03-06T22:21:54Z |
| format | Journal article |
| id | oxford-uuid:5556fcfc-0d7e-4bb8-b38f-4686fbb2651f |
| institution | University of Oxford |
| last_indexed | 2024-03-06T22:21:54Z |
| publishDate | 2018 |
| publisher | MDPI |
| record_format | dspace |
| spelling | oxford-uuid:5556fcfc-0d7e-4bb8-b38f-4686fbb2651f2022-03-26T16:43:22ZA comparison of selective pressures in plant X-linked and autosomal genesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5556fcfc-0d7e-4bb8-b38f-4686fbb2651fSymplectic Elements at OxfordMDPI2018Krasovec, MNevado, BFilatov, D <p>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 <i>Silene latifolia</i> 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 <i>Silene</i> 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 <i>S. latifolia</i> X-linked genes (π<sub>x</sub> = 0.016; π<sub>aut</sub> = 0.023). Thus, the faster-X divergence in <i>S. latifolia</i> 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.</p> |
| spellingShingle | Krasovec, M Nevado, B Filatov, D A comparison of selective pressures in plant X-linked and autosomal genes |
| title | A comparison of selective pressures in plant X-linked and autosomal genes |
| title_full | A comparison of selective pressures in plant X-linked and autosomal genes |
| title_fullStr | A comparison of selective pressures in plant X-linked and autosomal genes |
| title_full_unstemmed | A comparison of selective pressures in plant X-linked and autosomal genes |
| title_short | A comparison of selective pressures in plant X-linked and autosomal genes |
| title_sort | comparison of selective pressures in plant x linked and autosomal genes |
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