Sequence Variation at Exon 5 of GH Gene of Different Bovine Species

Characters of sequence variation at exon 5 of GH(growth hormone) gene of three bovine species(Leiqiong cattle,Yak and Mongolia cattle from Xinjiang Autonomous Region) were analyzed based on sequencing.Together with the cited sequences of other species(cattle,zebu cattle and buffalo),the molecular phylogenetic tree was therefore built to probe phylogenetic relationship between Bovine subfamilies.Total 5 variation sites were examined and two types of mutation,transition and transversion,were observed,with the average percentage of nucleotide variation of 1.66%.It demonstrated the poverty of polymorphism at exon 5 of GH gene of three bovine species. There was only one missense mutation out of 5 mutation sites which led to the shift between leu and val amino.Bos taurus(cattle) was clusterd with Bos indicus(zebu cattle) firstly,then clustered with Bos grunniens(yak) and with Bubalus bubalus(buffalo) lastly,which was in accordance with prior classification.The results were in favour of the opinions that Southern China might be a cradle of Bos indicus and that gene intercourse might have occured between Bos grunniens and Bos indicus in the process of evolution.