Phylogenetic analysis and characterization of mitochondrial DNA for Korean native cattle

This study was aimed to preserve mitochondria from liver tissues of Korean native cattle (KNC) as genetic resources and to analyze phylogenetic relationships among cattle breeds using the whole sequences of mtDNA. Mitochondria of KNC has been isolated with the alkaline lysis procedure using 1 g of liver tissues, and measurements showed numbers of cells (2.64 × 10), concentration (114.6 ug/ml), proteins (0.278 ug/ml), and absorbance (0.029) in 260 nm. Mitochondrial DNAs (mtDNA) were extracted from the isolated mitochondria to determine whole sequences that can be used to estimate genetic distances among cattle breeds. Designing of primers based on the bovine mtDNA sequence was resulted in 16 primer sets covering the whole mtDNA regions. The analysis of 40 KNC mtDNA sequences revealed 69 polymorphic sites that were less than the average number of SNP (single nucleotide polymorphism) for other populations (82 sites) in this study. As expected, the highest observation of SNPs was found in the D-loop region, and a total of 29 SNPs were shared between cattle populations. The haplotype analysis, which used 13 SNPs located in D-loop, COX2, ND5, CYTB, and non coding regions, revealed that KNC showed clearly different haplotypes that may be used to distinguish KNC from other breeds as well as to characterize individual identifications. The phylogenetic analysis revealed that KNC showed a relatively close genetic distance with Japanese black cattle (JBC) comparing with other breeds. Estimations of the average nucleotide diversity (0.0008) and the ratio of transition/ transversion (0.1050) of KNC were placed somewhere in the middle of genetic diversity among cattle breeds. The identified genetic variants and results of phylogenetic analysis will help understanding the phylogenetic relationships of KNC and provide useful genetic information for further studies regarding SNPs in mtDNA regions.