Disentangling the relationship between sex-biased gene expression and X-linkage.
Genome Res
; 22(7): 1255-65, 2012 Jul.
Article
in En
| MEDLINE
| ID: mdl-22499666
ABSTRACT
X chromosomes are preferentially transmitted through females, which may favor the accumulation of X-linked alleles/genes with female-beneficial effects. Numerous studies have shown that genes with sex-biased expression are under- or over-represented on the X chromosomes of a wide variety of organisms. The patterns, however, vary between different animal species, and the causes of these differences are unresolved. Additionally, genes with sex-biased expression tend to be narrowly expressed in a limited number of tissues, and narrowly expressed genes are also non-randomly X-linked in a taxon-specific manner. It is therefore unclear whether the unique gene content of the X chromosome is the result of selection on genes with sex-biased expression, narrowly expressed genes, or some combination of the two. To address this problem, we measured sex-biased expression in multiple Drosophila species and at different developmental time points. These data were combined with available expression measurements from Drosophila melanogaster and mouse to reconcile the inconsistencies in X-chromosome content among taxa. Our results suggest that most of the differences between Drosophila and mammals are confounded by disparate data collection/analysis approaches as well as the correlation between sex bias and expression breadth. Both the Drosophila and mouse X chromosomes harbor an excess of genes with female-biased expression after controlling for the confounding factors, suggesting that the asymmetrical transmission of the X chromosome favors the accumulation of female-beneficial mutations in X-linked genes. However, some taxon-specific patterns remain, and we provide evidence that these are in part a consequence of constraints imposed by the dosage compensation mechanism in Drosophila.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
X Chromosome
/
Dosage Compensation, Genetic
/
Drosophila
/
Genes, X-Linked
/
Genetic Linkage
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Genome Res
Journal subject:
BIOLOGIA MOLECULAR
/
GENETICA
Year:
2012
Document type:
Article
Affiliation country:
Estados Unidos