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

Abstract

Many cases of introgressive hybridization have been reported among birds, in particular after the introduction in the natural environment of animals belonging to a taxon close to the native one. This appears to be the case for common quail (Coturnix coturnix) in France where wild populations are artificially put in contact with domesticated Japanese quail (Coturnix japonica) raised for production but sometimes released for hunting purposes. In order to highlight the possible existence of gene flow 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 that the two taxa were clearly differentiated by the panel, making it possible to seek for the existence of hybrids among quails sampled in the wild. Nine birds expected to be common quail were not: they were two pure Japanese quail, one backcross to C. japonica, three F1, and one backcross and two advanced generations of backcross to C. 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.