Genetic Diversity Analysis Of Fine Wool Sheep Populations Based On Microsatellite Markers

In order to investigate the status of genetic resources of China fine wool sheepand get hold of their genetic structure and breeding potential, We selected ChineseMerino (Xinjiang type), Chinese Merino superfine strains, Xinji super–fine woolsheep, Aohan fine wool sheep, Gansu alpine Merino, Gansu alpine Merino superfinestrains and Qinghai Merino as research subjects and the contol groups include Husheep and Liangshan semi–fine wool sheep using10microsatellite DNA markers byfluorescence PCR. The markers were recommended by the Food and AgricultureOrganization of the United Nations (FAO) and the International Socitety for AnimalGenetics (ISAG). A wide range of statistical analyses were performed on experimentaldata to answer questions about population genetic diversity, genetic relationship anddifferentiation. The results are as follows:It is linkage disequilibrium for10microsatellite loci, which are highlypolymorphic in the nine sheep populations, so they can be used as effective markersof genetic diversity and population genetic relationship analysis.The average polymorphism information content was0.6938of seven fine woolsheep populations, and the average heterozygosity was0.7353, and the average allelerichness was7.4343, indicating that the genetic diversity of the population wasabundant; the Hardy-Weinberg equilibrium test results showed Gansu alpine Merinosuperfine strains and China Merino superfine strains deviated balance more than5loci. The results remind us should strengthen this variety breeding or cross-breeding.Clustering analysis by unweighted pair-group method with arithmetic mean(UPGMA) and the scatter plots using principal component analysis showed that9sheep populations were classied two groups-the fine wool sheep populations, Husheep and Liangshan semi–fine wool sheep. The genetic distance of Gansu alpineMerino and Qinghai Merino genetic were closer, meanwhile the genetic distance ofChinese Merino (Xinjiang type), Chinese Merino superfine strains, Xinji super-finewool sheep, Aohan fine wool sheep, Gansu alpine Merino superfine strains were closer. It indicated that the genetic structure of the populations is clear.Genetic differentiation analysis showed that genetic differentiation coefficient(Fst) of seven fine wool sheep populations was very low, were less than0.05. Thegene flow between Chinese Merino (Xinjiang type) and Xinji super–fine wool sheepwas the strongest31.30, and was lowest8.02between Qinghai Merino and Aohan finewool sheep. The large gene flow among populations may be one of the main reasonsleading to a low degree of genetic differentiation among these groups. Inbreedingcoefficient within each group are negative values indicating heterozygote excess,which may be caused by large gene flow or continue to import foreign amongpopulations. The results showed that the effect of combined breeding and directionalbreeding was obvious.