Genetic Polymorphic Analysis And Anticipation Of Heterosis Of Meat Sheep In Ningxia Autonomous Region

Using the method of"random sampling in typical colonies of the habitat", the genetic diversities of 6 sheep breeds populationsin Ningxia Autonomous Region were analyzed with the microsatellite marker technology. The sheep breeds were as followings: Dorset, Texel, Black-Suffolk, Tan sheep, Small-tailed Han sheep, hybrid of Tan and Small-tailed Han sheep. The thesis discussed the genetic variation within population and among populations, kinship and anticipated heterosis. The results were followed:1. The 105 alleles were found in 7 microsatellite loci, and all the loci had more than 5 alleles in each population. The most was 20 in MAF70, the second was 17 in OarAE101.The least was 12 in BMS1714. The average effective number of allele in 7 loci was all more than 4. The Dorset had the most effective number of allele, which was 8.2216, and the TH hybrid had the least effective number of allele, which was 5.4633.2. The results showed that all 7 loci had highly dominant alleles and 5 loci had private alleles. In this study, all 7 loci displayed high diversity, the PIC value varied from 0.7000 to 0.8000. The PIC value in locus MAF70 was the highest (0.8729), in locus OarAE101 was the smallest (0.7189). The most value was 0.8546 in Dorset and the least was 0.7188 in Tan sheep. The mean heterozygosity of different locus varied from 0.2638 to 0.4885, and to different population was from 0.2901 to 0.4534, all loci and populations can be recognized as middle heterozygosity.3. The F-statistic analysis indicated that the extent of inbreeding in the six populations was low, 6.98% hereditary variation was caused among populations, while 93.02% genetic variation was from individual variation within populations. Coefficients of gene differentiation among domestic varieties and introduced varieties were larger than that in them. The gene flow among domestic and introduced varieties was lower than that in domestic varieties.4. According to DA and DC genetic distances, the methods of UPGMA was used to draw the dendrograms: the 6 sheep populations were divided into 2 groups: the one group were introduced varieties, Texel and Black-Suffolk clustered first and then clusted with Dorset, the other one were domestic varieties: Tan sheep and Small-tailed Han sheep clustered first, TH hybrid sheep then clusted with them.