Potentialities of Japanese quail Coturnix japonica as a genetic resource

In this study, Japanese quail (Coturnix japonica ) were classified into two categories, i.e., wild and domestic. Gene frequencies in each population, degree of genetic variability within populations, and genetic differentiation between populations were investigated. An attempt was made to find changes and improvements in genetic constitution in various stages of domestication by comparing the results of wild and domestic quail populations . The positive average inbreeding coefficient values (F sup(IS)) of Wright (1965) were obtained for all wild quail populations. Conversely, negative F sup(IS) values were obtained for most of the domestic quail populations. This may have been due to the blending of strains in populations that occurred in the course of improvement of the domestic quail. Hence, the results demonstrated that the level of genetic variability of the domestic quail populations was higher than that of the wild ones. The degree of genetic differentiation among the domestic quail populations was higher than that among the wild populations. Although the degree of differentiation was very small, the quail populations could be separated into the following two clusters : domestic and wild in the dendrograms illustrated by genetic distance of Nei (1975). These results suggest that, in the case of quail, domestication has not caused any drastic change in gene pools because the history of domestication is not long. Japanese quail populations still have great susceptibility to a number of deleterious genetic effects, such as inbreeding depression. When the problems of inbreeding depression are settled and quail breeds are established, the industry will make rapid progress. Domestic quails will also be improved as an experimental animal. Japanese quail are competent as a material to elucidate the mechanism of inbreeding depression . They are also competent as a pilot animal for preservation and proliferation of endangered bird populations, and an indicator animal for environmental monitoring.