Some mammals breed throughout the year, while others breed only at certain times of year. These differences in reproductive behavior can be explained by evolution. We identified positively-selected genes in two sets of species with different degrees of relatedness including seasonal and non-seasonal breeding species, using branch-site models. After stringent filtering by sum of pairs scoring, we revealed that more genes underwent positive selection in seasonal compared with non-seasonal breeding species. Positively-selected genes were verified by cDNA mapping of the positive sites with the corresponding cDNA sequences. The design of the evolutionary analysis can effectively lower the false-positive rate and thus identify valid positive genes. Validated, positively-selected genes, including CGA, DNAH1, INVS, and CD151, were related to reproductive behaviors such as spermatogenesis and cell proliferation in non-seasonal breeding species. Genes in seasonal breeding species, including THRAP3, TH1L, and CMTM6, may be related to the evolution of sperm and the circadian rhythm system. Identification of these positively-selected genes might help to identify the molecular mechanisms underlying seasonal and non-seasonal reproductive behaviors.
[1]S China Univ Technol, Sch Biosci & Bioengn, Guangdong Prov Key Lab Fermentat & Enzyme Engn, Guangzhou 510641, Guangdong, Peoples R China.
[2]Guangdong Lab Anim Monitoring Inst, Guangdong Key Lab Lab Anim, Guangzhou, Guangdong, Peoples R China.
[3]Chinese Peoples Liberat Army Gen Hosp, Beijing 100853, Peoples R China.
[4]Fudan Univ, Sch Life Sci, Shanghai 200433, Peoples R China.
[5]Tibet Univ, Inst Biodivers Sci, Lhasa, Peoples R China.
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