Litter size and meat quality are economically important quantitative traits in pig industry, variations of which are under the regulations of polygenes and major genes. Recently, it has been proved that both ESR and PRLR were key factors to regulate the inheritance of reproduction traits in pigs, and both RN and RYR1 were proved to be genes with large genetic effect on meat quality traits as well. Obviously, it is very important to explore the characteristics of genotypic distribution of these loci because ...