Study On Genetic Diversity Of MtDNA And Molecular Phylogeny Evolution In Six Chinese Indigenous Buffalo Types

China is one of the countries that have the richest swamp buffalo resources in the world. The native buffalo types in China are not only expensive natural resources but also economic resources with high values. Because of lacking comprehensive and systematic knowledge on the genetic diversity and characteristics of indigenous buffalo types, we only used the native breeds as the female parents and the foreign breeds as the male parents to hybrid, which has led to the decline of the genetic diversity of buffalo gradually and even the distinct of some genetic resource of buffalo soon. So it is helpful to the conservation and utilization of animal breed resources to study the buffalos'genetic diversity. Through analyzing the mtDNA D-loop of 54 samples from 6 Chinese indigenous buffalo types with the published in GenBank about the river buffalo and the swamp buffalo mtDNA D-loop in Brazil and Italy,we studied the maternal origin of the buffalos, the phylogenetic relations between genetic varieties and diversity and got these results as follows.1.23 hyplotypes were detected in 54 Chinese buffalo samples. The average nucleotide content are: 27.58% for T, 33.75% for A, 15.30% for G and 26.37% for C. Average (A+T) content is 58.33% and 41.67% for (G+C), A+T the former is apparently higher than the latter, it is suggesting that the base bias which is in proportion to mammalian mitochondrial DNA nucleotide composition.2.54 sites are polymorphic in 23 hyplotypes with 6.12% of 915 bp D-loop region, 51 of these sites are transitions, 3 of them are transvertions, 2 of these sites have both transitions and transvertions.3.The length of the complete mtDNA D-loop sequences varied from 910bp to 920 bp in 54 individuals of 6 Chinese buffalo types. The haplotype diversity and nucleotide diversity were 0.533～0.953 and 0.0011～0.0204, respectively, indicating abundant genetic diversity in Chinese buffalo populations.4.NJ phylogenetic and a reduced median network analysis in Chinese buffalo mtDNA revealed two highly divergent, namely lineages A and B. The frequency of the lineage A and B was 65% and 35%, respectively, which suggested that Chinese native buffalo may have two maternal origins.5.Combined data from Brazil and Italy river bufflao and swamp buffalo, the NJ phylogenetic tree and reduced median network showed two main branches: the river buffalo branch and the swamp buffalo branch, and the latter consisted of lineages A and B.