title: Parallel sites implicate functional convergence of the hearing gene prestin among echolocating mammals.
abstract: Echolocation is a sensory system whereby certain mammals navigate and forage using sound waves, usually in environments where visibility is limited. Curiously, echolocation has evolved independently in bats and whales, which occupy entirely different environments. Based on this phenotypic convergence, recent studies identified several echolocation-related genes with parallel sites at the protein sequence level among different echolocating mammals, and among these, prestin seems the most promising. Although previous studies analyzed the evolutionary mechanism of prestin, the functional roles of the parallel sites in the evolution of mammalian echolocation are not clear. By functional assays, we show that a key parameter of prestin function, 1/α, is increased in all echolocating mammals and that the N7T parallel substitution accounted for this functional convergence. Moreover, another parameter, V1/2, was shifted toward the depolarization direction in a toothed whale, the bottlenose dolphin (Tursiops truncatus) and a constant-frequency (CF) bat, the Stoliczka's trident bat (Aselliscus stoliczkanus). The parallel site of I384T between toothed whales and CF bats was responsible for this functional convergence. Furthermore, the two parameters (1/α and V1/2) were correlated with mammalian high-frequency hearing, suggesting that the convergent changes of the prestin function in echolocating mammals may play important roles in mammalian echolocation. To our knowledge, these findings present the functional patterns of echolocation-related genes in echolocating mammals for the first time and rigorously demonstrate adaptive parallel evolution at the protein sequence level, paving the way to insights into the molecular mechanism underlying mammalian echolocation.
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Laboratory of Evolutionary and Functional Genomics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Laboratory of Evolutionary and Functional Genomics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, ChinaUniversity of the Chinese Academy of Sciences, Beijing, China.
authors.forename: Fei-Yan
authors.initials: FY
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Laboratory of Evolutionary and Functional Genomics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Laboratory of Evolutionary and Functional Genomics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: Hai-Qing
authors.initials: HQ
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Laboratory of Evolutionary and Functional Genomics, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China ship@mail.kiz.ac.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Shi
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D004455:Echolocation; D019143:Evolution, Molecular; D057809:HEK293 Cells; D006309:Hearing; D006801:Humans; D008322:Mammals / Q000145:classification / Q000235:genetics* / Q000502:physiology; D010802:Phylogeny
chemical_list: D027321:Anion Transport Proteins
keywords: NLC; bat; convergent evolution; dolphin; echolocation