Molecular Evolution Of Genes Related To Protein Metabolism In Sable And Its Adaptation To Cold

The Sable(Martes zibellina),is a kind of weasel which is widely distributed in the high latitude area of the Eurasian continent.Because of the high economic value of fur,it was over hunted in a long period in the past,now it is the national first grade protected wildlife in China.In order to adapt to the cold environment,sable has developed several survival strategies,such as energy metabolism and fur development.Protein is not only an important component of organism,but also an important metabolic substance to generate energy,animals can adapt to the cold by increasing the metabolic heat production of protein,sugar and fat.Based on the adaptive evolution of sable protein metabolism for cold,this study analyzes the molecular evolution of protein metabolism-related genes in carnivora to explore the molecular mechanism of protein metabolism during cold adaptation.The following is the main results of the research:1.Using PAML,Datamonkey and other biological software to analyze the selection pressure of genes about protein metabolism in sable.12 positive selection genes were detected by branch model and branch-site model in sable,COL4A2 detected positive selection by branch model,COL5A1,COL6A1,MTR,KMT2 A and other 11 genes detected positive selection by branch-site model.GCDH,COL15A1,ARG1,ATP1B3 and CARNS1 detected positively selected in the mustelidae,means these genes have an adaptive evolution in mustelidae including sable.2.The results of three-dimensional protein structure prediction showed that the positive selection sites of LDHB,ADSSL1,ALDH4A1,PFKL,GSTO2,CAT,ARG1,ATP1B3 and CARNS1 genes were located in the irregular curl region,the positive selection sites of MTR gene were located in the fold sheet layer,the positive selection sites of KMT2 A gene were located in the spiral region,the positive selection sites of DDC and COL16A1 gene were located in the spiral region,the fold sheet layer and the irregular curl region and so on.And,the 122 nd site of ADSSL1 gene,the 399 th and the 401 th positive selection sites of CAT gene,all the sites except the 16 th site of DDC gene,the 224 th site of MTR gene,the 395 th site of PFKL gene,and all positive selection sites of ARG1,ATP1B3 and CARNS1 genes,are in the conservative domain,indicating that the positive selection of these sites may affect the structure and function of their proteins.3.The positive selection genes play a role in the absorption of amino acids,the regulation of protein and carbohydrate metabolism,the increase of energy production in the process of metabolism and the harmful substances in the process of protein synthesis.At the same time,DDC and KMT2 A may be related to the movement coordination and circadian rhythm of sable.COL4A2,COL5A1 and COL6A1 encode collagen,which may be related to the rapid repair of tissues damaged by metabolic endogenous proteins when sables obtain sufficient energy to survive.In summary,our results show that there are several genes related to energy producted in metabolism of sable,which means that the genes related to protein metabolism of sable can be adapted by increasing metabolic heat production in cold environment.At the same time,there are several positive selection genes related to the absorption of amino acids,the transformation of harmful substances in the process of protein metabolism and the synthesis of essential amino acids,which may make sable have a more stable process of protein metabolism.And multiple genes that encoding collagen are being positive selected,which mean sable can repair of tissues that damaged by endogenous proteins when food shortage caused by cold.We preliminarily revealed the role of protein metabolism related genes in cold adaptation of sable by this study.