Genetic Diversity Of Changtai Yak At Protein And Gene Levels

The main objective of this study was to investigate the genetic diversity ofChangtai yak population in Sichuan province at molecular level, and to identify theirgenetic relationships with Maiwa yak breed and Jiulong yak breed, in order to providescientific data for the utilization of Changtai yak genetic resources. Comprehensiveanalysis and comparison of the genetic diversity of Changtai yak, Maiwa yak andJiulong yak in Sichuan province were carried out using15microsatellite loci,mitochondrial DNA (mtDNA) D-loop sequence, an expressed sequence ofmini-satellite (the epithelial mucin of milk, MUC1), and the unique polymorphisms ofthe lactate dehydrogenase-1(LDH-1) and the duplication fragmet of κ-casein (κ-CN)in yak. The main results are as follows:1. The analysis using microsatellite, mini-satellite and mtDNA D-loop showedthe three yak breeds/populations with a high degree of polymorphisms. The geneheterozygosity (Ho) and haplotype diversity (Hd) in Changtai yak were higher than inMaiwa yak and Jiulong yak.2. The analysis by means of mtDNA D-loop sequencing revealed that the geneticdistances were similar among the three yak breeds/populations, suggesting their closergenetic relationship on maternal origin; Polymorphisms analysis of microsatellite andMUC1showed that Changtai yak had closer association with Maiwa yak. Togetherwith polymorphism characterstics of LDH1and κ-CN in the three yakbreeds/populations, we proposed that Changtai yak had a closer genetic relationshipwith Maiwa yak than with Jiulong yak.3. This is the first report of genetic diversity of Changtai yak with amulti-analysis at molecular level, and Changtai yak may represent an independent yakpopulation based on the cluster analysis with Maiwa yak breed and Jiulong yak breed.4. A simple method of PCR and electrophoresis was established to detecte the12-bp duplication polymorphisms in exon4of yak κ-casein gene.