Molecular Evolution Of The Glycogen Synthase 1 Gene (Gys1) In Bats (Chiroptera)

Bats (Order:Chiroptera), have fell into diverse food habits during their long-term evolution. There are insectivorous, piscivorous, carnivorous, sanguivorous, frugivorous and nectarivorous bats. Old World fruit bats (OWFB) (Family: Pteropodidae) and New World fruit bats (NWFB) (Family:Phyllostomidae) independently evolved high-carbohydrate diets comprising mainly of fruit, nectar and pollen. Whether they have evolved special mechanisms to avoid high-carbohydrate consumption has been a hot issue during a long time. Glycogen synthase, which catalyzes the synthesis of glycogen, is especially important for Old World (Pteropodidae) and New World (Phyllostomidae) fruit bats. Glycogen synthase 1, encoded by the Gysl gene, is the glycogen synthase isozyme that functions in muscles. To determine whether Gysl has undergone adaptive evolution in bats with carbohydrate-rich diets, in comparison to insect-eating sister bat taxa, we sequenced the coding region of the Gysl gene from 10 species of bats, including two Old World fruit bats (OWFBs) (Pteropodidae) and a New World fruit bat (NWFBs) (Phyllostomidae). Our results show no evidence for positive selection in the Gysl coding sequence on the ancestral OWFBs and the NWFB Artibeus lituratus branches. Test for convergent evolution indicated convergence of the sequences and one parallel amino acid substitution (T395A) was also detected on these branches, which was driven by natural selection.