Effect of increasing the density of the markers on the accuracy of predicted breeding values genomic

In this study، the genome consists of 3 chromosomes، each 100cM with different marker density (100 markers with 1cM space، 200 markers with 0. 5cM space، 1000 markers with 0. 1cM space and 2000 markers with 0. 05cM space) and 30 random distributed QTL were simulated. After 50 generations of random mating in a finite population (Ne=100) to create sufficient linkage disequilibrium، population size were expanded by 1000 (500 males and 500 females). This structure was conserved until generation 58. Two heritability (h2=0. 1 and h2=0. 5) were considered. Individuals of generation 51 and 52 have phenotype records and then used to estimate marker effects. Accuracy of genomic estimated breeding value (GEBV) was calculated for individuals of generations 51-58. Results of first trial showed that accuracy of GEBV will increase by increasing in marker density for high heritability traits، but it increase to some extent (markers with 0. 1cM space) for low heritability traits and it decrease by more dense markers. Results in second trial which used half of individuals of generation 51 and 52 for marker effect estimation، showed that accuracy of GEBV will decrease by decreasing in number of individual. In both trials، accuracy of GEBV for high heritability traits was higher than low heritability traits in same marker density. Finally، results of this study showed that accuracy of GEBV will decease by passing generations after generations used for marker effect estimation