Genetic Diversity Analysis With Microsatellite DNA On 7 Sheep Populations

The microsatellite loci are used in this erperiment to analysis the genetic diversity of 396 sheep from one indigenous breed (Small Tail Han sheep) and six introduced breeds (Black Suffolk, White Suffolk, Texel, Dorper, South African Mutton Merino, East Friesian). It can be offered the basis of conversation and utilization of indigenous sheep breeds resource. We get some results as following:1. Based on the 15 microsatellites loci, we analyze the genetic variation of 7 sheep breeds and get 122 alleles and 8.1 in average, which show that the indigenous sheep have highly genetic diversity.2. We get the allele frequency with the POPGENE program. Accordingly, we calculate H, PIC and Ne and, which is 0.0345～0.8833, 0.2354～0.7110, 1.0351～7.7781 respectively. The result show that the genetic variations is abundant.3. The genetic diversity of indigenous breed is higher than the introduced breeds on Na, Ne, Ho, He and PIC.4. Almost all of the loci were not in the HD-W equilibrium through the test of HD-W with x² in 7 sheep breeds.5. We calculate the Ht,Hs and Gst. We find the genetic varitation between populations is 16.25% of that of total population. We safely draw a conclusion that the genetic variation between populations is not high , the genetic variation within population is the main source of the total variation.6. We get the D_A and D_S genetic distance by the DISPAN program. The results show that the genetic distance among populations vary inapparently. According to the two genetic distances, we make NJ and UPGMA cluster. The reconstruct tree show that D_A/NJ dendrogram give a real genetic relationship with 7 breeds , and NJ cluster is better used in this study.7. The F-statistic analysis indicated that the F_ST of different locus varied from 0.0869 (in MCM150) to 0.3099 (in MCM25), the average was 0.1625. The Nm was from 0.5567 (in MCM25) to 2.6283 (in MCM150), and the mean value was 1.2885.