Genetic Diversity Among Chinese Sheep Breeds Based On Microsatellite Markers

Genetic diversity is an important part of biodiversity.The abundance extent of genetic diversity reflects the historical background,adaptability,evolution tendency and the under duress degree of the species. Therefore, it is a kind of method to reveal genetic background,population dynamics,genetic structure and mutation of species through the research of genetic variance on microsatellite site. The genetic diversity of nine Chinese indigenous sheep breeds( Sunite sheep,Lanzhou tailed sheep,Tan sheep,Kazak sheep,Hetian sheep,Cele sheep,Jinzhong sheep,Wadi sheep,Zhaotong sheep ) are tested with fluorescence PCR using 10 microsatellite markers recommended by the FAO and ISGA in this paper.It Calculates genetic heterozygosity,polymorphism information content,allele number,F-statistics,genetic distanceand genetic differentiation coefficient of the groups.The genetic structure is evaluated based on the principal component analysis method between groups.The test results take down:1. Between nine sheep breeds,the average polymorphism information content and the average observed heterozygosity are highly polymorphic.The average effective alleles number is higher.Tt shows that the genetic diversity of populations is rich.The average polymorphism information content and the average observed heterozygosity are both highly polymorphic on 10 microsatellite seats.Tt indicates that the ten sites can effectively be used to assess the genetic diversity on groups.2. 153 alleles and 32 rare alleles are detected in nine sheep breeds.The average number of alleles is ranged from 5.7 to 8.7.The average effective number of alleles is varied from 3.2434 to 4.9847.This above shows the nine populations are highly polymorphic.The genetic diversity is rich and the genetic basis is extensive on groups.3. F-statistics and evaluation of genetic diversity degree show that:The genetic variation between populations is less in total variation.Genetic variation mainly comes from the interior of population. There is some inbreeding with different degree within groups.4. Hardy-Weinberg balance is detected among breeds.In the heterozygosity deficit,heterozygosity excess and possibility test,groups deviate from the equilibrium with different degree.It shows that group structure is being destroyed.5. The populations can be divided into four groups by DA/ UPGMA cluster based on the genetic distance:Wadi sheep and Jinzhong sheep are together,and then kazak sheep gathers to the class;Hetian sheep and CeLe sheep gather to a class; Lanzhou tailed sheep and Tan sheep are together originally,and then Sunite sheep gathers to this class; Zhaotong sheep is alone for a class; The four classes clusteres together finally.6. The conclusion of the genetic structure relationship and DA/UPGMA dendrogram and MVSP cluster analysis diagram is basically consistent with sheep origin and evolution and genetic structure and variationand geographic distribution.