Chinese Holstein Cattle Shows a Genetic Contribution from Native Asian Cattle Breeds: A Study of Shared Haplotypes and Demographic History

The Chinese Holstein cattle breed, an introduced breed in China, has been crossbred with native cattle breeds.We hypothesised that the Chinese Holstein local population in Beijing share haplotypes with native Asian cattle breeds, the result of a sudden population expansion in the recent past.We also hypothesised that crossbreeding and population expansion left traces that shaped the genetic makeup of the breed.Evaluation of this was performed by mitochondrial DNA (mtDNA) sequence analysis of Chinese Holstein cattle from Beijing (n = 41) and a comparison of them with the published mtDNA sequences (n = 293) of 14 Asian breeds with an emphasis on Chinese native cattle breeds.Three shared common haplotypes between Chinese Holstein cattle and native Asian cattle were found.Moreover, a high level of haplotype diversity in Chinese Holstein cattle (h = 0.9557) and low nucleotide diversity (π = 0.0052) was found, indicating a past population bottleneck followed by rapid population growth.These findings are supported by the significantly negative deviation of Tajima's D (-1.82085), the star-like pattern of dominant haplotypes and the pairwise mismatch distribution analysis, which showed a unimodal pattern.(