Molecular Clock Test And Phylogenetic Status Of Leiqiong Cattle And Haizi Water Buffalo Based On Analysis Of Sequences Of Cytochrome B Gene And Alcohol Dehydrogenase Gene

Sixteen and fifteen sequences of coding gene cytochrome b (cytb) in mitochondrial DNA of Leiqiong cattle and Haizi water buffalo, respectively, and for alcohol dehydrogenase (ADH) gene including the fifth, sixth, seventh and eighth exons in genome, they were both eighteen sequences, after a series of PCR reaction and sequencing. So, frequency value more than 0.3478 was reliable according to the number of sequences of both genes. two mutations and three different haplotypes were found when cytochrome b(cytb) gene sequences of sixteen Leiqiong cattle were analyzed, and for Haizi water buffalo they were ten mutations and two different haplotypes. As to ADH gene, three mutations and five different haplotypes were found when eighteen gene sequences of Leiqiong cattle were analyzed, and for Haizi water buffalo they were no mutation. Do BLAST with each haplotype of both cytb gene and ADH gene, and eight cytb gene sequences of Bovinae animals were selected, they were Bos indicus(AF419237), Bos Taurus( DQ186214), Bos grunniens (AY374124), Bubalus arnee carabanesis (AY702618), Bubalus arnee bubalis (AF547270), Bubalus depresscornis (D88641) ,Bubalus mindorensis (D82895) and Syncerus caffer (D82888), with Ovis aries (DQ459341) as the outgroup. As to ADH gene , seven homologous sequences found were all selected including Canis familiaris (XM₅35667), Pongo pygmaeus(CR858591), Macaca mulatta (XM₀01099784), Macaca fascicularis (AK240628), Equus caballus (NM₀01082528), Pan troglodytes (XM₀01166683), and Sus scrofa (AK233380) together with sequences of Bos grunniens, Bos Taurus and Bos frontalis from our lab. The results of molecular clock test and phylogenetic trees analysis indicated that: (1) revolution rate was not invariable for distant relative species as to both mitochondrial gene (cytb) and genome gene, and molecular clock hypothesis was rejected, but molecular clock hypothesis was accepted when gene sequences of close relative species were analyzed, so it might be absolute for non- invariable evolution rate, and relative for invariable and random molecular evolution. (2) ADH gene differentiation was before formation of species of bos, and the differentiation perhaps happened at the same time of differentiation of each genus of Bovinae animals.(3) there were rich genetic polymorphism and particular variation locus for Leiqiong cattle according to gene sequences analysis of both cytb and ADH, and BLAST search. sequences of ADH gene of Haizi water buffalo were identical, and the differentiation of ADH gene might happened at the same time of differentiation of each genus of Bovinae animals, so ADH gene of Chinese native water cattle might be lack of polymorphism. It was the first time to report the two termination codon of cytb gene AGG and AGA, and AGG was the unique termination codon only found in Haizi water buffalo by now. (4) In matriline origin analysis, swamp buffalo(Chinese buffalo) and river buffalo(Indian buffalo) are two independent species of Bubalus the same as lowland anoa (Bubalus depresscornis)and tamaraw(Bubalus mindorensis).(5) there might be two matriline origins in Haizi water buffalo, so there might be at least two matriline origins in Chinese existent water buffalo.