Molecular evolution of the ATP-binding cassette subfamily G member 2 gene subfamily and its paralogs in birds

Shengchao Ma, Hehe Liu, Wenqiang Sun, Ahsan Mustafa, Yang Xi, Fajun Pu, Yanying Li, Chunchun Han, Lili Bai, He Hua
2020 BMC Evolutionary Biology  
ATP-binding cassette (ABC) transporters are involved in the active transportation of various endogenous or exogenous substances. Two ABCG2 gene subfamily members have been identified in birds. A detailed comparative study of the ABCG2 and ABCG2-like genes aid our understanding of their evolutionary history at the molecular level and provide a theoretical reference for studying the specific functions of ABCG2 and ABCG2-like genes in birds. We first identified 77 ABCG2/ABCG2-like gene sequences
more » ... the genomes of 41 birds. Further analysis showed that both the nucleic acid and amino acid sequences of ABCG2 and ABCG2-like genes were highly conserved and exhibited high homology in birds. However, significant differences in the N-terminal structure were found between the ABCG2 and ABCG2-like amino acid sequences. A selective pressure analysis showed that the ABCG2 and ABCG2-like genes were affected by purifying selection during the process of bird evolution. We believe that multiple members of the ABCG2 gene subfamily exist on chromosome 4 in the ancestors of birds. Over the long course of evolution, only the ABCG2 gene was retained on chromosome 4 in birds. The ABCG2-like gene on chromosome 6 might have originated from chromosome replication or fusion. The structural differences between the N terminus of ABCG2 protein and those of ABCG2-like proteins might lead to functional differences between the corresponding genes.
doi:10.1186/s12862-020-01654-z pmid:32664916 fatcat:2kovmypcmrdpvabyw7gf4jjjvm