Study On The Molecular Evolution And Phylogeny Of Mitochondrial DNA D-loop Sequence Polymorphic In Yellow Cattle

The mitochondrial DNA control region complete sequence of 50 individuals from 8 yellow cattle breeds were individually determined. The results showed:Chinese yellow cattle complete sequence of mtDNA D-loop was 910 bp, 91 lbp and912 bp. 59 sites were polymorphic (6.48% in 910) ,with 9 singleton polymorphic sites and 50 parsimony informative polymorphic sites. There were five kinds of mutation of nucleotide. They were transition, transverstion, insertion/deletion and the coexistence of transition and transvertion. This research defined 23 haplotypes, in which haplotype H4 is major haplotypes of Chinese yellow cattle. The distribution and frequency of all the haplotypes intraspecies and interspecies were disequilibration. Average haplotypes disversity of haplotypes was from 0.500-0.9444, Average genetic distance was 0.018 (0.000-0.051) of which indicated the abundance of haplotypes of Chinese yellow cattle's D-loop. Kimura 2-parameter distance between yellow cattle breeds were individually 0.000-0.048. It indicated that Chinese yellow cattle's genetic diversity is abundant. The curve of nucleotcide mismatch distributions in yellow cattle population took on unimodal and wavilness. Tajima's test of selective neutrality was not significant (P>0.10). It revealed that yellow cattle population did not undergo expansions.There were gene flow and significant divergence among Chinese yellow cattle breeds.This research adopted D-loop's haplotypes of yellow cattle and correlative sequences from GenBank, using software Mega2.1 and Paup4.0 to construct NJ-tree and MP-tree of D-loop complete sequence,The topology structures of different phylogeny trees were similar and discrepancies are not significant (P>0.05). It indicated that phylogeny trees were accuracy. The phylogeny trees shows that the D-loop's haplotypes of yellow cattle branch divide into Indian zebu branch and Europe cattle branch. It revealed that Bos taurus and Bos indicus were the two origins of yellow cattle population in China, and the turine probably had more influence on the Chinese yellow cattle population than Zebu did. whether the Chinese yellow cattle have the banteng origin or not depend on the more research.