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Why do some sex chromosomes degenerate more slowly than others? The odd case of ratite sex chromosomes

Yazdi, Homa Papoli LU ; Silva, Willian T.A.F. LU orcid and Suh, Alexander (2020) In Genes 11(10). p.1-13
Abstract

The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes... (More)

The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes in ratites is not clear. Degeneration of the W chromosome might have halted or slowed down due to a multitude of reasons ranging from selective processes, such as a less pronounced effect of sexually antagonistic selection, to neutral processes, such as a slower rate of molecular evolution in ratites. The production of genome assemblies and gene expression data for species of Palaeognathae has made it possible, during recent years, to have a closer look at their sex chromosome evolution. Here, we critically evaluate the understanding of the maintenance of recombination in ratites in light of the current data. We conclude by highlighting certain aspects of sex chromosome evolution in ratites that require further research and can potentially increase power for the inference of the unique history of sex chromosome evolution in this lineage of birds.

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author
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organization
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type
Contribution to journal
publication status
published
subject
keywords
Chromatin state, Recombination, Sex chromosome, Sexual antagonism
in
Genes
volume
11
issue
10
article number
1153
pages
13 pages
publisher
MDPI AG
external identifiers
  • scopus:85091856504
  • pmid:33007827
ISSN
2073-4425
DOI
10.3390/genes11101153
language
English
LU publication?
yes
id
f3979c1b-5f50-488d-a587-a30b4de28ee3
date added to LUP
2020-11-02 15:13:36
date last changed
2024-05-15 20:43:19
@article{f3979c1b-5f50-488d-a587-a30b4de28ee3,
  abstract     = {{<p>The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes in ratites is not clear. Degeneration of the W chromosome might have halted or slowed down due to a multitude of reasons ranging from selective processes, such as a less pronounced effect of sexually antagonistic selection, to neutral processes, such as a slower rate of molecular evolution in ratites. The production of genome assemblies and gene expression data for species of Palaeognathae has made it possible, during recent years, to have a closer look at their sex chromosome evolution. Here, we critically evaluate the understanding of the maintenance of recombination in ratites in light of the current data. We conclude by highlighting certain aspects of sex chromosome evolution in ratites that require further research and can potentially increase power for the inference of the unique history of sex chromosome evolution in this lineage of birds.</p>}},
  author       = {{Yazdi, Homa Papoli and Silva, Willian T.A.F. and Suh, Alexander}},
  issn         = {{2073-4425}},
  keywords     = {{Chromatin state; Recombination; Sex chromosome; Sexual antagonism}},
  language     = {{eng}},
  number       = {{10}},
  pages        = {{1--13}},
  publisher    = {{MDPI AG}},
  series       = {{Genes}},
  title        = {{Why do some sex chromosomes degenerate more slowly than others? The odd case of ratite sex chromosomes}},
  url          = {{http://dx.doi.org/10.3390/genes11101153}},
  doi          = {{10.3390/genes11101153}},
  volume       = {{11}},
  year         = {{2020}},
}