Lack of nucleotide polymorphism in the Y-linked sperm flagellar dynein gene Dhc-Yh3 of Drosophila melanogaster and D. simulans.
We studied levels of intra- and interspecific nucleotide variation associated with a Y-linked gene in five members of the Drosophila melanogaster subgroup. Using published sequence for 348 bp of the Dhc-Yh3 gene, and degenerate PCR primers designed from comparisons of the sea urchin and Chlamydomonas flagellar dynein genes, we recovered a 1738-bp region in D. melanogaster. Analyses of sequence variation in a worldwide collection of 11 lines of D. melanogaster and 10 lines of D. simulans found only a single silent polymorphism in the latter species. The synonymous site divergence per site for Dhc-Yh3 is comparable to values for X and autosomal genes. Assuming a Wright-Fisher population model, the lack of variation is statistically less than expected using appropriately reduced estimates of theta from the X and autosomes. Because the Y chromosome encodes only six known genes, genetic hitchhiking associated with background selection is unlikely to explain this low variation. Conversely, adaptive hitchhiking, as associated with sex-ratio chromosomes, or a large variance in male fertility may reduce the polymorphism on the Y chromosome. Codon bias is very low, as seen for other genes in regions of low recombination.
Zurovcova
M
M
Department of Ecology and Evolution, State University of New York, Stony Brook, New York 11794, USA.
Eanes
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WF
D000818:Animals; D001483:Base Sequence; D004330:Drosophila / Q000235:genetics*; D004398:Dyneins / Q000235:genetics*; D008040:Genetic Linkage; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013082:Sperm Tail / Q000378:metabolism*; D014998:Y Chromosome
D012333:RNA, Messenger; D004398:Dyneins