Retrogene movement within- and between-chromosomes in the evolution of Drosophila genomes.
Recent genomic analyses in Drosophila and mammals of inter-chromosomal retroposition have revealed that during evolution the retroposed genes that show male-biased expression tend to leave the X chromosome and opt for autosomal positions. Such a phenomenon may be a process of general, genomic and evolutionary relevance. It contributed to the unexpected overrepresentation of male-biased genes on the autosomes recently observed in microarray expression experiments. In this paper, we report our genomic analysis of within-chromosomal retroposition in Drosophila melanogaster, and compare it with the previously identified pattern of the between-chromosomal retroposition. We find that a surfeit of autosomal retroposed genes originated from parental genes located on the same chromosome, in contrast to the X chromosome in which only few genes retroposed in cis. Such an autosomal proximity effect implicates a role of the mutation process for retroposition in determining chromosomal locations of autosome-derived retroposed genes. Furthermore, this phenomenon supports the hypothesis that natural selection favors the retroposition of genes out of the X chromosome. Analyses of a large expression database for D. melanogaster genes revealed that the vast majority of the X-derived autosomal retroposed genes had evolved testis expression functions, consistent with other previous genomic analyses.
Dai
Hongzheng
H
Committee on Genetics, The University of Chicago, 1101 E 57th Street, Chicago, IL 60637, USA.
Yoshimatsu
Toshio F
TF
Long
Manyuan
M
D000818:Animals; D005075:Biological Evolution; D004330:Drosophila / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D049750:Genome, Insect; D008297:Male; D008957:Models, Genetic; D018626:Retroelements; D012730:Sex Chromosomes / Q000235:genetics
D018626:Retroelements