gene dropping analysis of founder contributions and allelic diversity in an under selected population of japanese quails

The current study was conducted to consider how pedigree and the gene-dropping analysis can use to moni-tor genetic diversity, and to recommend a breeding strategy for improving breast weight (brw) in a population of japanese quail. a total of 312 birds were divided equally into two lines. one line (s1) was selected for four-week body weight (bw) based on breeding value, and the other (s2) was selected for four-week brw based on between-family selection. the distributions of allele frequencies originating from the foun-ders were estimated using gene-dropping simulation software for the actual pedigree of each line. the re-sults revealed that the total net genetic improvements in bw and brw in the s1 and s2 lines were 28.3 and 9.7 g vs. 23.3 and 6.8 g, respectively. the average numbers of surviving alleles in the descendants were 59.6 and 31.2 for the s1 and s2 lines, respectively, which were 19.1% and 10% of the total number of as-signed alleles in the base population. it can be concluded that for stabilizing the response to selection for improving brw, it is recommended to use indirect selection of bw based on breeding values. the results obtained from the gene-dropping experiment showed that the between-family selection method results nei-ther in more genetic gain nor in greater remaining genetic variation.