Evidence of Echolocation in the Common Shrew from Molecular Convergence with Other Echolocating Mammals.

Abstract

Along with sophisticated echolocation found in bats and toothed whales, the common shrew (Sorex araneus) was confirmed to possess echolocation ability based on behavioral and experimental evidence such as high-frequency twittering and close-range spatial orientation. However, whether echolocation in the common shrew is convergent with bats and dolphins at the molecular level remains poorly understood. In this study, we gathered the coding region sequences of 11 hearing-related genes from genome data and previous studies. Convergent evolutionary analyses identified 13 amino acid residues (seven in CDH23, five in OTOF, and one in PRESTIN) under strong convergent evolution shared among the common shrew and other echolocating mammals (bats and dolphins). Furthermore, a phylogenetic tree was constructed based on the combined amino acid dataset of convergent/parallel substitutions, sites with parallel radical property changes, and sites supporting echolocator-convergence; it supported the converged topology of the simple echolocator Sorex araneus and sophisticated echolocating bats with high posterior probability. This study gives evidence at the molecular level that the common shrew echolocate and provides novel insights into the convergent evolution between the common shrew and bats and dolphins.