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Sex-biased gene expression on the avian z chromosome: highly expressed genes show higher male-biased expression.

Naurin, Sara LU ; Hasselquist, Dennis LU ; Bensch, Staffan LU and Hansson, Bengt LU (2012) In PLoS ONE 7(10).
Abstract
Dosage compensation, the process whereby expression of sex-linked genes remains similar between sexes (despite heterogamety) and balanced with autosomal expression, was long believed to be essential. However, recent research has shown that several lineages, including birds, butterflies, monotremes and sticklebacks, lack chromosome-wide dosage compensation mechanisms and do not completely balance the expression of sex-linked and autosomal genes. To obtain further understanding of avian sex-biased gene expression, we studied Z-linked gene expression in the brain of two songbirds of different genera (zebra finch, Taeniopygia guttata, and common whitethroat, Sylvia communis) using microarray technology. In both species, the male-bias in gene... (More)
Dosage compensation, the process whereby expression of sex-linked genes remains similar between sexes (despite heterogamety) and balanced with autosomal expression, was long believed to be essential. However, recent research has shown that several lineages, including birds, butterflies, monotremes and sticklebacks, lack chromosome-wide dosage compensation mechanisms and do not completely balance the expression of sex-linked and autosomal genes. To obtain further understanding of avian sex-biased gene expression, we studied Z-linked gene expression in the brain of two songbirds of different genera (zebra finch, Taeniopygia guttata, and common whitethroat, Sylvia communis) using microarray technology. In both species, the male-bias in gene expression was significantly higher for Z than for autosomes, although the ratio of Z-linked to autosomal expression (Z:A) was relatively close to one in both sexes (range: 0.89-1.01). Interestingly, the Z-linked male-bias in gene expression increased with expression level, and genes with low expression showed the lowest degree of sex-bias. These results support the view that the heterogametic females have up-regulated their single Z-linked homologues to a high extent when the W-chromosome degraded and thereby managed to largely balance their Z:A expression with the exception of highly expressed genes. The male-bias in highly expressed genes points towards male-driven selection on Z-linked loci, and this and other possible hypotheses are discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
7
issue
10
publisher
Public Library of Science
external identifiers
  • wos:000309454000095
  • pmid:23056488
  • scopus:84867094991
ISSN
1932-6203
DOI
10.1371/journal.pone.0046854
project
Sex chromosome evolution and sex-biased expression
CAnMove
language
English
LU publication?
yes
id
2651aa5c-9771-4b60-b14e-17f067cdf8ec (old id 3160839)
date added to LUP
2012-11-02 14:05:15
date last changed
2017-01-01 07:53:24
@article{2651aa5c-9771-4b60-b14e-17f067cdf8ec,
  abstract     = {Dosage compensation, the process whereby expression of sex-linked genes remains similar between sexes (despite heterogamety) and balanced with autosomal expression, was long believed to be essential. However, recent research has shown that several lineages, including birds, butterflies, monotremes and sticklebacks, lack chromosome-wide dosage compensation mechanisms and do not completely balance the expression of sex-linked and autosomal genes. To obtain further understanding of avian sex-biased gene expression, we studied Z-linked gene expression in the brain of two songbirds of different genera (zebra finch, Taeniopygia guttata, and common whitethroat, Sylvia communis) using microarray technology. In both species, the male-bias in gene expression was significantly higher for Z than for autosomes, although the ratio of Z-linked to autosomal expression (Z:A) was relatively close to one in both sexes (range: 0.89-1.01). Interestingly, the Z-linked male-bias in gene expression increased with expression level, and genes with low expression showed the lowest degree of sex-bias. These results support the view that the heterogametic females have up-regulated their single Z-linked homologues to a high extent when the W-chromosome degraded and thereby managed to largely balance their Z:A expression with the exception of highly expressed genes. The male-bias in highly expressed genes points towards male-driven selection on Z-linked loci, and this and other possible hypotheses are discussed.},
  articleno    = {e46854},
  author       = {Naurin, Sara and Hasselquist, Dennis and Bensch, Staffan and Hansson, Bengt},
  issn         = {1932-6203},
  language     = {eng},
  number       = {10},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Sex-biased gene expression on the avian z chromosome: highly expressed genes show higher male-biased expression.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0046854},
  volume       = {7},
  year         = {2012},
}