Evidence for introgressive hybridization of wild common quail (Coturnix coturnix) by domesticated Japanese quail (Coturnix japonica) in France

Many cases of introgressive hybridization have been reported among birds, particularly following introduction to the natural environment of individuals belonging to non-native similar taxa. This appears to be the case for common quail (Coturnix coturnix) in France where wild populations artificially come into contact with domesticated Japanese quail (Coturnix japonica) raised for meat and egg production but sometimes released for hunting purposes. In order to highlight the possible existence of gene flows between both taxa, a comparison of nuclear (25 microsatellite loci) and mitochondrial (sequencing and RFLP) DNA polymorphisms was performed on 375 common quails (from France, Spain and Morocco) and 140 Japanese quails (from France and Japan). Genetic diversity was assessed, and analyses (Factorial Correspondence Analysis, Bayesian admixture) of molecular polymorphisms revealed clear differentiation between the two taxa, making it possible to detect for hybrids among quails sampled in the wild. Eight birds expected to be common quail were found to be two pure Japanese quail, one probable backcross to C. japonica, three F1/F2 hybrids, and two probable backcrosses to Coturnix coturnix. These results show that Japanese quails were released and suggest that the two taxa hybridize in the wild. They confirm the urgent need for preventing the release of pure Japanese or hybrid quails to preserve the genetic integrity of C. coturnix. The tools developed for this study should be useful for accurate monitoring of wild quail populations within the framework of avifauna management programs.