Cytochrome b shows signs of adaptive protein evolution in Gerbillus species from Egypt

Abstract

Amino acid polymorphisms in the mitochondrial cytochrome b (cytb) gene of four Gerbillus species have been investigated for their geographical distribution and possible functional significance. The sequences were obtained from a total of 20 specimens representing four species of genus Gerbillus collected from Siwa Oasis, Dabaa, Wadi El Natron, El Faiyum, and Baltim in Egypt. Our results identified a group of amino acid variant polymorphisms that were useful for both species taxonomic and biogeographic assignments. The results demonstrated that amino acid variants L>F173 (Leucine>Phenylalanine), A>M203 (Alanine>Methionine), and I>V221(Isoleucine>Valine) were specific to G. andersoni, while the variant V>M283 (Valine>Methionine) was only specific to G. andersoni from Baltim. The variants, L>P263 (Leucine>Proline) and M>T311 (Methionine>Threonine) were specific only to G. amoenus collected from El Faiyum. Compared to other amino acid variants, L>P263 was remarkably less frequent, and it was predicted using PROVEAN database tool to have non-neutral effects. Amino acid polymorphisms within the cytochrome b gene could be assigned to specific geographic locations. They might prove suitable to track accumulated and recent environmental changes as they could represent signs of adaptive evolution.