Research And Discussion On The Adaptive Evolutionary Mechanism And Phylogenetic Relationship Related To The Feeding Habits Of Mammals

In this paper,we utilized comparative genomic tools and methods of phylogenetic to discuss two research subjects.The first one is adaptive evolution to a high purine and fat diet by the genomes.The other one is Construction and discussion of whole-genome phylogeny of mammals by alignment-free Method.The main contents are as follows:1.There are over 250 species in the order Carnivora 1,most of the which are carnivorous(CA,e.g.Felidae,Canidae).However,some of the species are omnivorous(OC,e.g.Procyonidae,Mephitidae)and herbivorous(HC,e.g.the giant panda and red panda(Ailurus fulgens).The CA members reside at the apex of food chains and consume a diet rich in purines,fats and protein derived from animal meat and carrion.However,long-term consumption of meat diets is known to promote the occurrence of several serious conditions including gout and cardiovascular disease in humans.We utilized comparative genomic tools to identify adaptive evolutionary signatures compatible with high purine and fat metabolism.The genome scan analysis of carnivorans revealed TLR6(involved in innate immunity and insulin resistance under high fat diet)and GPR17,GPR34,PDE4DIP,DYSF and LRRC15 genes(associated with cardiovascular function)were under positive selection.Together,carnivorous carnivorans appear to endure diets rich in purines and fats through the occurrence of genomic adaptations that reduce the risks of disease associated with this diet.2.The alignment-free methods have been used to analyze genomic or proteomic sequence by characterizing and comparing the statistical feature of sequences,or the frequencies of certain kmer within sequences.These methods have unique advantages for summarying the overall feature of omic data since it takes into account the influence of all the variation types on the whole sequence.In this work,a phylogenetic relationships of NJ trees were established using the CVTree software based on the alignment-free method,which include the proteome data of 45 mammalian species.We discussed several issues on phylogenetic relationships of mammals according to these trees.On the relation of four superorders within Eutheira,our results provided evidence for the hypothesis of epistheria,which was in line with the morphological conclusion but different from the Exafro-Placentalia hypothesis mainly supported by sequence alignment methods.At order level,the tree is primarily consistent with the phylogenetic relationships accepted by both morpholigical and molecular evidence.But within the order level there are more discrepancies.The results show that the alignment-free method is available in phylogenetic study using omic data for complex multicellular creatures.The improvement of the alignment-free method itself and its comparison with traditional sequence alignment method still need more in-depth studies.