title: Adaptive evolution of the STRA6 genes in mammalian.
abstract: Stimulated by retinoic acid 6 (STRA6) is the receptor for retinol binding protein and is relevant for the transport of retinol to specific sites such as the eye. The adaptive evolution mechanism that vertebrates have occupied nearly every habitat available on earth and adopted various lifestyles associated with different light conditions and visual challenges, as well as their role in development and adaptation is thus far unknown. In this work, we have investigated different aspects of vertebrate STRA6 evolution and used molecular evolutionary analyses to detect evidence of vertebrate adaptation to the lightless habitat. Free-ratio model revealed significant rate shifts immediately after the species divergence. The amino acid sites detected to be under positive selection are within the extracellular loops of STRA6 protein. Branch-site model A test revealed that STRA6 has undergone positive selection in the different phyla of mammalian except for the branch of rodent. The results suggest that interactions between different light environments and host may be driving adaptive change in STRA6 by competition between species. In support of this, we found that altered functional constraints may take place at some amino acid residues after speciation. We suggest that STRA6 has undergone adaptive evolution in different branch of vertebrate relation to habitat environment.
authors.affiliation: Inner Mongolia Prataculture Research Center, Chinese Academy of Science, Hohhot, China; Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
authors.forename: Jianghong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xiang
authors.affiliation: Inner Mongolia Prataculture Research Center, Chinese Academy of Science, Hohhot, China; Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Inner Mongolia Prataculture Research Center, Chinese Academy of Science, Hohhot, China; Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Ding
authors.initials: D
authors.lastname: Yang
authors.affiliation: Inner Mongolia Prataculture Research Center, Chinese Academy of Science, Hohhot, China; Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Inner Mongolia Prataculture Research Center, Chinese Academy of Science, Hohhot, China; Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Hailian
authors.initials: H
authors.lastname: Sun
authors.affiliation: Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Animal Husbandry Institute, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
mesh_terms: D000220:Adaptation, Biological; D020816:Amino Acid Motifs; D000818:Animals; D019143:Evolution, Molecular; D005123:Eye / Q000378:metabolism; D006801:Humans; D008322:Mammals / Q000235:genetics*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D010802:Phylogeny; D012641:Selection, Genetic
chemical_list: D008565:Membrane Proteins; C519685:STRA6 protein, human