Abstract :
To determine the genetic diversity and phylogenetic relationships among Chinese sheep,
10 indigenous breeds and one introduced breed were genotyped for 19 microsatellite
loci. The mean number of alleles per breed ranged from 5.44 (Guide Black Fur sheep)
to 9.13 (Ujumqin sheep and Hulunbeier sheep), the expected heterozygosity varied
from 0.623 (Guide Black Fur sheep) to 0.737 (Zhaotong sheep), and the allelic richness
ranged from 5.169 (Guide Black Fur sheep) to 7.610 (Zhaotong sheep). The deviation
from Hardy–Weinberg equilibrium (HWE) was statistically significant (P < 0.05) at three
loci (SRCRSP5, OarAE129 and DYMS1) in most of the breeds. Chinese sheep breeds had
maintained a high level of within-population genetic differentiation (95.23%), with the
remainder explained by differentiation among populations (4.77%). The genetic differentiation
pattern and genetic relationships among Chinese sheep breeds displayed a high
consistency with the traditional classification. Both the Bayesian cluster and principal component
analyses showed a reliable clustering pattern, which revealed three major clusters
in Chinese indigenous sheep (Mongolian sheep, Kazakh sheep and Tibetan sheep), except
Zhaotong and Guide Black Fur sheep. There were probably caused by different breeding history,
geography isolation and different levels of inbreeding. This study will help to interpret
the genetic characters of Chinese indigenous sheep and benefit to the future conservation
programs.
