High frequency hearing is necessary for bats to prey, orientation and navigation when the echolocation is used. Although echolocation is usually associated with bats, it is not the characters of all bats. Most bats take advantage of echolocation to adapt the unique niche of dark sky except the Pteropodidae. Otherwise, tooth whales also have echolocation to adapt underwater environment where lack of light. So, echolocation bats and tooth whale had convergent evolution in phenotype of echolocation, and this yield out two questions: one is that did bats and tooth whale own same molecular mechanism to adapt the similar environment? And another question is that did bats achieve the echolocation which had relationship with high hearing frequency in the initial ancient of bats or evolved independently in microbats? Previous studies have focused on the morphological and molecular data to resolve these questions. It still is a gap to solve these questions using functional evidence. In this paper, we combine molecular data and functional evidence to try to resolve these questions. In our study, we chose prestin as our candidate gene which has been identified as a hearing gene and has close relationship to high frequency hearing. Our result comes from site mutation and functional experiments indicate that echolocating mammals went through the convergent evolution in function of prestin, and divergence in different parameters, which are also correlated with mammalian high-frequency hearing. Furthermore, we found that the some convergent sites of prestin between echolocating mammals caused the functional divergence due to the interactions between sites. To our knowledge, these findings for the first time present the functional patterns of echolocation-related genes in echolocating mammals and reveal the different roles of convergent sites for prestin function, paving the way to insights into the molecular mechanism underlying mammalian echolocation. Similarly, to solve the controversial question about did echolocation evolved once or more than once we reconstructed bats ancestors prestin sequences? Combine with functional data we found the echolocation of bats probably achieved since the origin of bats evolved. Fortunately, two parallel evolution sites were found in bat common ancestor prestin sequence, and we induce these two sites are the molecular bases of bats common ancestor achieved the ability of echolocation. This study is the first time to shed light on the origin of echolocation with functional evidence. Considering lack of fossil evidences, ancestral sequences reconstruction and function terrifying provide a novel approach to study the ancestor hearing of bats.
修改评论