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Patterns of molecular evolution of an avian neo-sex chromosome.

Pala, Irene LU ; Hasselquist, Dennis LU ; Bensch, Staffan LU and Hansson, Bengt LU (2012) In Molecular Biology and Evolution 29(12). p.3741-3754
Abstract
Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In the present study, we report the results of molecular analyses of neo-Z and neo-W gametologues and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe (i)... (More)
Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In the present study, we report the results of molecular analyses of neo-Z and neo-W gametologues and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe (i) lower genetic diversity of neo-Z genes comparatively to autosomal genes, (ii) moderate synonymous and weak non-synonymous sequence divergence between neo-Z and the neo-W gametologues and (iii) lower GC content on neo-W than on neo-Z gametologues. Phylogenetic reconstruction of eight neo-Z and neo-W gametologues suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e. after approximately 42.2 MYA) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e. after approximately 39.4 36 MYA). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes, but as expected from its more recent origin shows weaker divergence between gametologues. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
recombination cessation, ZW gametolog divergence, avian neo-sex chromosome
in
Molecular Biology and Evolution
volume
29
issue
12
pages
3741 - 3754
publisher
Oxford University Press
external identifiers
  • wos:000310970000012
  • pmid:22826461
  • scopus:84869074287
ISSN
0737-4038
DOI
10.1093/molbev/mss177
project
Sex chromosome evolution and sex-biased expression
CAnMove
language
English
LU publication?
yes
id
c4fc314c-2e8c-49ae-a566-a8939979809f (old id 2966718)
date added to LUP
2012-09-05 14:29:44
date last changed
2017-10-22 03:15:30
@article{c4fc314c-2e8c-49ae-a566-a8939979809f,
  abstract     = {Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In the present study, we report the results of molecular analyses of neo-Z and neo-W gametologues and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe (i) lower genetic diversity of neo-Z genes comparatively to autosomal genes, (ii) moderate synonymous and weak non-synonymous sequence divergence between neo-Z and the neo-W gametologues and (iii) lower GC content on neo-W than on neo-Z gametologues. Phylogenetic reconstruction of eight neo-Z and neo-W gametologues suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e. after approximately 42.2 MYA) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e. after approximately 39.4 36 MYA). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes, but as expected from its more recent origin shows weaker divergence between gametologues.},
  author       = {Pala, Irene and Hasselquist, Dennis and Bensch, Staffan and Hansson, Bengt},
  issn         = {0737-4038},
  keyword      = {recombination cessation,ZW gametolog divergence,avian neo-sex chromosome},
  language     = {eng},
  number       = {12},
  pages        = {3741--3754},
  publisher    = {Oxford University Press},
  series       = {Molecular Biology and Evolution},
  title        = {Patterns of molecular evolution of an avian neo-sex chromosome.},
  url          = {http://dx.doi.org/10.1093/molbev/mss177},
  volume       = {29},
  year         = {2012},
}