Molecular Evolution Of The Ribonuclease5(RNase5) Gene In Chiroptera

As the second biggest animal group in mammals, Chiroptera (bats) demonstrates many unique adaptive features in terms of flight, echolocation, auditory acuity, feeding habit, hibernation and immune defense, providing an excellent system for understanding the molecular basis of how organisms adapt to the living environments encountered. In the first part of this paper, we review the researches on the molecular mechanism of the adaptive evolution of Chiroptera, especially about the recent researches at the genome levels, which suggesting a far more complex evolutionary pattern and functional diversity than previously thought.In the second part, we studied the molecular evolution of the RNase5gene in Chiroptera. RNase A is a specific-enzyme family for vertebrates, which are important for the origin of genes and the generation of new functions. Many members belongs to RNaseA undergone gene duplication and expericed positive seletion. Compired to the other members of RnaseA, each of which has including8cysteines, RNase5has6cysteines and its main function is angiogenesis and host defence. In this study, we selected the RNase5gene as reseach object, based on38representative species belongs to25genera and10families. The results showed that:(1) in Yinpterochiroptera, the rhinolophidae belongs to rhinolophidea and pteropodidae detected gene duplication; however, in the two the other families hipposideridae and megadermatidae, the gene was single-copied; in Yangochiroptera, the single-copied gene was detected in phyllostomatidae/mormoopidae and emballonuroidae; interestingly, in the families Miniopterinae, vespertilionidae and Molossidae of the superfamily vespertilionidea, we detected gene duplication; then, one pseudogene was found in the two familes mormoopidae and emballonuroidae, implying that the function was not indispensable in these families.(2) all of genura belongs to vespertilionidea undergone gene duplication, especilly, in the genus Myotis, we detected numberous gene copies, implying3gene duplications and6pseudogenizations. Migration was the especial feature in Chiroptera, and all of species of Myotis migrate usually for a short distance, thus may leading to the expansion of niche in prey animals, the the function of host defense in predators undergone adaptive evolution.(3) positive selection has been displayed delightful aspects for us:among the two ancestor branches of the Molossidae and Myotis, we detected the choice of action and positive site, as well as in copy gene cluster of Myotis, and the positive sites were nearby cysteine. In the future, along with the increasing numbers of available Chiroptera species genomes, new evolutionary patterns and functional divergence will be revealed, which can promote the further understanding of this animal group and the molecular mechanism of adaptive evolution.