mtDNA Diversity and Origin of Chinese Mongolian Horses

In order to learn the origin of the Chinese Mongolian horse, we analyzed polymorphisms within the mtDNA D-loop variable region in 305 horses of 6 types of 3 different breeds, including one imported breed, one cultivated breed and 4 types of one local breed. We detected 13 different haplotypes, and subsequent sequence analysis showed that all 6 horse types were genetically diverse. By constructing a cladogram of mtDNA D-loop sequences from the 6 horse types along with homologous sequences from several other horse types obtained from GenBank, we showed that Chinese Mongolian horses have a close genetic relationship with other horse types from Mongolia. We also speculate that several Chinese Mongolian horses descended from Przewalskii horse. Additionally, the 13 haplotypes were dispersed throughout the cladogram, suggesting that Chinese Mongolian horses likely originated from multiple female ancestors. A phylogenetic map of the 6 horse types showed that the genetic relationship between the local Wuzhumuqin and Wushen types were the closest. The Xinihe and Baerhu were also closely related to each other, and slightly more distantly related to the cultivated Sanhe breed. All five of the local Chinese horse types had a much more distant relationship with the imported Thoroughbred breed.