Analysis The Polymorphism Of Mitochondrial Gene And Study The Relationship In Chinese Cattle

The single strand conformation polymorphism combined with DNA sequencing of control region in mitochondrial DNA was to study the genetic relationship of 15 cattle breeds (one cultivated breed, 3 foreign breeds and 11 Chinese native breeds) totaling 526.Meanwhile the polymorphism of 12SrRNA gene in mtDNA was examined. The result showed:The 15 cattle breeds had the high variation in the HV1 region of D-loop sequence within or between breeds, especially of Chinese native cattle breeds. D-loop region indicated 6 haplotypes by SSCP, so according it 79 individuals were sequenced. Analyzing the 79 sequences by MEGA3.1 showed: there were 94 polymorphism sites which is about 25.1% of the all detected sites in the 79 sequences. In it 72 sites belonged to parsim-imformative sites and 22 sites belonged to singleton site. Nucleotide variation was transitional, transvertional or insert/absent. 79 sequences revealed 56 different haplotype sequences. The 2 individuals of Fuzhou cattle breeds (FZ41 and FZ37) sequences which were different from others leaded to many variation sites.Studied the phylogenetic relationship by MEGA3.1 and Network4.1.1.2 then found there were 3 maternal origins: Bos indicus, Bos tauras and an unknown type which formed by FZ41 and FZ37.Comparaed sequences of the FZ41 and FZ37 with others sequences from NCBI found the two sequences weren't similar with the Yak, Bentang and shorthorn. The breeds except of Pingwu, Angus, Heifter and Fuzhou breeds had the different level of Bos indicus strain. Constructed genetic relationship by distance showed all the breeds divided into Bos indicus and Bos tauras. Bohai, Nanyang, Dabieshan were in Bos indicus and others were in Bos tauras. The Menggu, Yanbian and Chinese Simmental breeds were close and then clustering with other breeds. Though the Xiangxi cattle likes Bos indicus on outline but indeed it were Bos tauras through genetic relationship. This indicated that there was most Bos tauras strain in Xiangxi cattle.The SSCP marker detecting of 12SrRNA gene displayed 4 haplotypes. The haplotypeâ…¢andâ…£were lower frequency than haplotypeâ… andâ…¡. The 12SrRNA sequencing was...