title: Multiple bursts of pancreatic ribonuclease gene duplication in insect-eating bats.
abstract: Pancreatic ribonuclease gene (RNASE1) was previously shown to have undergone duplication and adaptive evolution related to digestive efficiency in several mammalian groups that have evolved foregut fermentation, including ruminants and some primates. RNASE1 gene duplications thought to be linked to diet have also been recorded in some carnivores. Of all mammals, bats have evolved the most diverse dietary specializations, mainly including frugivory and insectivory. Here we cloned, sequenced and analyzed RNASE1 gene sequences from a range of bat species to determine whether their dietary adaptation is mirrored by molecular adaptation. We found that seven insect-eating members of the families Vespertilionidae and Molossidae possessed two or more duplicates, and we also detected three pseudogenes. Reconstructed RNASE1 gene trees based on both Bayesian and maximum likelihood methods supported independent duplication events in these two families. Selection tests revealed that RNASE1 gene duplicates have undergone episodes of positive selection indicative of functional modification, and lineage-specific tests revealed strong adaptive evolution in the Tadarida β clade. However, unlike the RNASE1 duplicates that function in digestion in some mammals, the bat RNASE1 sequences were found to be characterized by relatively high isoelectric points, a feature previously suggested to promote defense against viruses via the breakdown of double-stranded RNA. Taken together, our findings point to an adaptive diversification of RNASE1 in these two bat families, although we find no clear evidence that this was driven by diet. Future experimental assays are needed to resolve the functions of these enzymes in bats.
authors: Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai 200062, China.
authors: Huihui
authors: H
authors: Xu
authors: Yang
authors: Y
authors: Liu
authors: Fanxing
authors: F
authors: Meng
authors: Beibei
authors: B
authors: He
authors: Naijian
authors: N
authors: Han
authors: Gang
authors: G
authors: Li
authors: Stephen J
authors: SJ
authors: Rossiter
authors: Shuyi
authors: S
authors: Zhang
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D002685:Chiroptera / Q000235:genetics*; D019143:Evolution, Molecular; D005247:Feeding Behavior; D020440:Gene Duplication; D008969:Molecular Sequence Data; D010802:Phylogeny; D011544:Pseudogenes; D012259:Ribonuclease, Pancreatic / Q000737:chemistry / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D012259:Ribonuclease, Pancreatic
keywords: AGT; Chiroptera; GLUT4; Gene duplication; Positive selection; RNASE1; RNase; RNase1; alanine-glyoxylate aminotransferase 1; glucose transporter 4; pancreatic ribonuclease; pancreatic ribonuclease gene; ribonuclease