The Study Of Molecular Evolution On Umima Taste Receptor (Tas1r1) Genes Of Carnivora

Taste is important in the diet to the animals, especially, the umami taste perception plays an important role in the food choice of carnivora because many of them main diet on meat. Species of carnivores from the diet can be divided into three categories, including meat-eater, omnivores and plant-eater. Carnivora species will undoubtedly become the preferred animals of the relationship between various diet and taste gene. There are many research on carnivorous about the geographic distribution and fossil in domestic and abroad, however, umarni receptor (Taslrl) gene as a molecular marker to study the molecular evolution and diet of carnivora groups is still less. Previous study which has been identified that the Taslrl pseudogenization in giant panda may be related to specific adaptation to diet switch its diet which99%of bamboo. They hypothesize that carnivora umami taste receptor (Taslrl) genes might be relaxed from selective constraints because of the change in diet. However, the Taslr1gene in many other groups of Carnivores has not been studied. In this study, we surveyed the Taslr1gene from three categories of carnivora, especially red pandas and giant pandas have very approximate the feeding habits, we speculated that Taslr1of the red panda may be have pseudogene phenomenon.In this experiment, the Taslrl gene as a molecular genetic markers, used some biology software, such as Premier5, DNAStar, ClustalX1.83, DNAMAN, MEGA5, PAML4.0, based on molecular systematics and bioinformatics methods to analysis and discussed of molecular evolution of the Carnivora. Some analysis including the sequence of amino acid composition, topology analysis, system development, selection pressure analysis, using neighbor-joining (NJ), the maximum likelihood (ML) reconstruction of the Carnivora part of the phylogenetic relationships among species. we obtain the following results:1):In this study, we first time obtained the coding sequences of Taslr1gene from seven species in the order carnivora, they are the badger, ferret badger, the Siberian tiger, leopard cat, red panda, black bear, masked palm civet. cDNA sequence of Taslr1gene in Camivora of full-length is2526bp, including the six exons. red pandas, black bears, masked palm civet, which measured the complete sequence, red pandas2525bp, black bear and civet cats2526bp, badger, ferret badger, Siberian tiger, leopard cat, a non-complete sequence of about2552bp.2):analysis of the Taslr1receptor gene sequences which have been measured by us, with the other species have been reported in GeneBank of the Taslr1receptor gene sequences, and found that there is lbp deletion in exon6of red panda Taslr1gene. The deletion of Taslr1receptor gene in red pandas leads to frameshift mutation, so we speculated that red pandas Taslr1receptor gene was a pseudogene. Contrast with other species, sequence analysis of carnivora showed that Taslr1receptor gene deletion only found in the giant pandas and red pandas;3):Selective test demonstrated that Taslr1is under strong purifying selection in the process of carnivora evolution; By PAML and branch model analysis, the ratios of non-synonymous to synonymous rateco (dN/dS) no significant difference in the strength of the selection in the three carnivora group, suggesting that between different feeding habits of carnivores are experiencing equal purifying selection, especially the giant pandas and red pandas which Taslrl receptor gene loss of function and the ω value is not significantly higher than other omnivores and carnivores;4):We also found that the sharing pseudogenization of Taslr1genes in the two pandas might be the result of convergent evolution during long-time adaptation to similar bamboo diet. According to the result of this experiment, the Taslr1receptor gene was pseudogene only found in species of giant pandas and red pandas in carnivoras, therefore, we can speculate that it’s possibly resulted from the unique bamboo diet because the pseudogenization was not found in other carnivora animals and herbivores such as cow and horse.