Analysis Of Mitochondrial DNA D-loop Genetic Diversity In Chinese Native Cattle

Mitochondrial DNA(mtDNA)has the characteristics of high mutation rate,non-recombination,maternal inheritance.It has been widely used in animal genetic diversity and origin evolution research.China’s cattle breeds/populations are extremely rich,with a clear geographical lineage structure and different germplasm characteristics compared to the foreign breeds.In comparison to the rich genetic resources of cattle in China,previous studies were not sufficient in characterizing the genetic diversity and origin of all Chinese cattle breeds/populations.So,14 Chinese local cattle breeds/populations including 459 samples(Mongolian,Lingnan,Dabieshan,Yiling,Huangpi,Sanjiang,Xiangxi,Guangfeng,Ji’an,Jinjiang,Weining,Dianzhong,Wenshan and Tibetan cattle breeds)were collected.The genetic diversity and origin and evolution of 459 cattle samples were analyzed using PCR amplification,sequencing and bioinformatics methods.Also,646 mtDNA D-loop sequences of Chinese local cattle were downloaded from GenBank.So,the genetic diversity and maternal origin of 1105 mtDNA D-loop sequences from 57 Chinese cattle breeds/populations were systematically analyzed in this study which will provide theory basis for the genetic resource protection and utilization of Chinese local cattle.The main results were as follows:(1)Chinese cattle have very rich mtDNA genetic diversity and originate from Bos taurus and Bos indicus.The study reveals the origin of Bos taurus and the introgression of yak genes in Tibetan cattle.(2)T1a lineage was mainly concentrated in the northeast region in Asia(including Northeast China,Korea and Japan).I2 lineage was mainly distributed in the southwest China(including Yunnan-Guizhou plateau and Tibet)and Xinjiang.(3)This is the first time that all five taurine haplogroups(T1a,T2,T3,T4 and T5)and two zubu haplogroups(I1 and I2)were found in Mongolian cattleThis study comprehensively analyzed the genetic diversity of mtDNA in Chinese cattle,and provided a theoretical basis for a comprehensive understanding of the genetic diversity,genetic structure and maternal origin of Chinese cattle breeds/populations.