Study On The Multiple Population Genome Selection Based On Simmental And Xuelong Beef Cattle

The GEBV are calculated as the sum of the effects of dense genetic markers,across the entire genome.The SNP effects were inferred from reference population in large scare population size with phenotypic information.The accuracy of genomic predication depends on sample size and the genetic relationship between reference population and validation population.The reliability of genomic predication depend heavily on the sample size and the genetic relationship between reference population and validation population.Combining data sets from multiple populations can provide an effective way to increase reliabilities,particularly when the sample size is small and phenotypes are difficult to measure.According to the results of simulation analysis,the accuracy of prediction based on mixed group was 0.74 when the two groups were derived from 5 generations,while the accuracy of the mixed group decreased to 0.18 when these populations were derived from 100 generations.Using the real dataset from 1 217 Chinese Simmental and 462 Xuelong cattle,we estimated the genetic parameter for six traits including growth,carcass and meat quality traits Our results suggested the estimated trait heritability for each trait varies from different breed.Among them,the carcass weight,the area of the eye muscle,the pre-mortem weight and the money tendon show high heritability,the daily gain weight have the middle and high heritability,while the shear force is low heritability.The estimated trait heritability ranged from 0.11 to 0.47 in two populations.Further,our conducted genome predication using both GBLUP and Bayes B methods in Simmental and Xuelong cattle,and the accuracy of the genomic prediction across these two groups was evaluated in mixed group.Our results suggested,for the single group,the average of accuracy of the genomic predication for the six traits using GBLUP method in the Chinese Simmental cattle was 0.359,which was 11% higher than those of Xuelong cattle.However,when mixed populations group were considered as reference,we found the accuracy of decreased by 22% and 26% in Simmental and Xuelong,respectively.In addition,we found,the accuracy of single group increased by 2% and 5% using Bayes B method when compared with the GBLUP method model,and the accuracy of mixed group increased by 8.7% and 18%,respectively.