Evidence for positive selection on Drosophila melanogaster seminal fluid protease homologs.
Proteins present in the seminal fluid of Drosophila melanogaster (accessory gland proteins Acps) contribute to female postmating behavioral changes, sperm storage, sperm competition, and immunity. Consequently, male-female coevolution and host-pathogen interactions are thought to underlie the rapid, adaptive evolution that characterizes several Acp-encoding genes. We propose that seminal fluid proteases are likely targets of selection due to their demonstrated or potential roles in between-sex interactions and immune processes. We use within- and between-species sequence data for 5 predicted protease-encoding Acp loci to test this hypothesis. Our polymorphism-based analyses find evidence for positive selection at 2 genes, both of which encode predicted serine protease homologs. One of these genes, CG6069, also shows evidence for consistent selection on a subset of codons over a deeper evolutionary time scale. The second gene, CG9997, was previously shown to be essential for normal sperm usage, suggesting that sexual selection may underlie its history of adaptation.
Wong
Alex
A
Department of Molecular Biology and Genetics, Cornell University, NY, USA. aw246@cornell.edu
Turchin
Michael C
MC
Wolfner
Mariana F
MF
Aquadro
Charles F
CF
D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D008297:Male; D008958:Models, Molecular; D010447:Peptide Hydrolases / Q000235:genetics*; D012641:Selection, Genetic; D012661:Semen / Q000201:enzymology; D029589:Seminal Plasma Proteins / Q000235:genetics*
D029721:Drosophila Proteins; D029589:Seminal Plasma Proteins; D010447:Peptide Hydrolases