Demasculinization of the Anopheles gambiae X chromosome

BMC Evolutionary Biology

Kalle Magnusson¹  Antonio M Mendes²  Gareth J Lycett³ 

[1] Department of Life Sciences, Imperial College London, London, UK;Division of Biology, California Institute of Technology, Pasadena, USA;Liverpool School of Tropical Medicine, London, UK

关键词: Anopheles gambiae;    demasculinization;    germline x-chromosome inactivation;    sexual antagonism;    dosage compensation;   

DOI  :  10.1186/1471-2148-12-69

学科分类：生物科学（综合）

来源: BioMed Central

【 摘 要 】

In a number of organisms sex-biased genes are non-randomly distributed between autosomes and the shared sex chromosome X (or Z). Studies on Anopheles gambiae have produced conflicting results regarding the underrepresentation of male-biased genes on the X chromosome and it is unclear to what extent sexual antagonism, dosage compensation or X-inactivation in the male germline, the evolutionary forces that have been suggested to affect the chromosomal distribution of sex-biased genes, are operational in Anopheles. We performed a meta-analysis of sex-biased gene expression in Anopheles gambiae which provides evidence for a general underrepresentation of male-biased genes on the X-chromosome that increased in significance with the observed degree of sex-bias. A phylogenomic comparison between Drosophila melanogaster, Aedes aegypti and Culex quinquefasciatus also indicates that the Anopheles X chromosome strongly disfavours the evolutionary conservation of male-biased expression and that novel male-biased genes are more likely to arise on autosomes. Finally, we demonstrate experimentally that transgenes situated on the Anopheles gambiae X chromosome are transcriptionally silenced in the male germline. The data presented here support the hypothesis that the observed demasculinization of the Anopheles X chromosome is driven by X-chromosome inactivation in the male germline and by sexual antagonism. The demasculinization appears to be the consequence of a loss of male-biased expression, rather than a failure in the establishment or the extinction of male-biased genes.

【 授权许可】

CC BY