Cloning Of SRY Gene From Moschus Berezovskii And Moschus Chrysogaster And The Prediction And Analysis Of SRY Protein's Structure And Its Application In Phylogenetic Analysis

CDS region of SRY gene were cloned from M. berezovskii and M. chrysogaster genomic DNA by PCR method with primers according to the known SRY sequences from Artiodactyla animals.The nucleotides sequences of SRY CDS were translated into amino acid sequences and were analyzed using softwares. It was found that there have a high nonsynonymous sbustitutions in HMG-box region between the M. berezovskii and M. chrysogaster, which suggested that in some degree the HMG-box is affected by the positive directional selection. It's important that the three-fourths nonsynonymous substitutions of SRY CDS take place in the HMG-box, higher than it's flanks.We analyzed the first strcture and predicted the secondary structure and the three-dimensional structure of SRY protein, and compare them with the database especially of human and mouse, and get the approximately equal structure. The component of SRY amino acids, character, structure domain and three-dimensional structure of SRY protein, especially of HMG-box region, were analyzed. The results showed that SRY protein of M. berezovskii and M. chrysogaster are hydrophilic, without signal peptide and transmembrane region, and they have some basic characteristics of regulator proteins. They have three helixes and their space tructure is the shape of "L" as same as the known SRY protein such as human.The HMG-box region was the important function region of SRY, and the SRY protein recognized the target sequences through the minor groove of DNA helix. Our research foundthat there have three nonsynonymous substitutions in HMG-box region of M. berezovskii and M. chrysogaster, which suggested that there might be a difference in the target sequences between them. It was worth thinking more about the difference because M. berezovskii and M. chrysogaster have very closed relationship.Sequences analysis from the point of the paternal inheritance were conducted and the SRY sequences from M. berezovski, M. chrysogaster, and some Cervidae, Bovidae animals, were used for phylogenetic tree construction with unweighted pair group method using arismetic average, (UPMGA), neighbor-joining (NJ) analysis of MEGA2.0 and maximum parsimony method (MP) analysis of PAUP4.0. The position of musk deer in the Artiodactyla evolution system and the evolutionary relationships with Artiodactyla especially with Cervidae were discussed using SRY sequences. The result of phylogeny showed that the musk deer formed a monophyletic group, which supported that the musk deer should be classified as an individual family Moschidae, instead of a subfamily or a genus. The phylogeny result is consistent with the result that constructed with Cyt b. It also suggested that short CDS of nuclear genes might provide enough information for studying the evolutionary relationship of some closed species.