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No Japanese quail genetic pollution in captive Common quail in Italy provides pure-bred stock for natural populations

18.09.2018: Hunting Common quails is a popular activity in the Mediterranean region. Experimental studies however showed that population re-stocking with farm-reared quails for hunting purposes is often done using Japanese quail or hybrids of domestic Japanese and Common quail. This could alter the gene pool of the native species and its migratory and reproductive behaviour, though direct evidence are lacking so far. Researchers from Vetmeduni Vienna have, for the first time, genetically screened a captive population of quails established from wild-caught birds to assess its genetic purity. The study revealed no evidence of Japanese quail genetic pollution and confirmed the success of the Common quails breeding programme of the native species as a feasible alternative to minimise the risk of genetic pollution of wild common quail populations.

Captive breeding programmes play an important role in the maintenance of wild animal populations. Restocking is regularly carried out with a variety of fish and bird species for recreational activities, such as fishing and hunting. Among birds, the Common quail is one of these species. The eggs of this rather inconspicuous migratory Galliform, as well as the animals themselves, are a popular treat and hunting trophy in the Mediterranean region. In Italy, France, Spain and Greece, quail farms have been established where the animals are bred and released to restock the local populations of these migratory birds.

For economic reasons, however, restocking has rarely been performed using the native common quail. Instead, domestic Japanese quails or hybrids have been considered to be easier to breed. Domestic Japanese quail, however, differ from their European relatives in a number of genetically and phenotypic traits, including a reduced (if any) level of migratory restlessness. Their release could therefore alter the makeup of the existing genepool with a gradual loss of native features and the original phenotype.

First genetic analysis of the risk presented by the use of Japanese quail in captive breeding

A team of experts from the Konrad Lorenz Institute of Ethology at Vetmeduni Vienna has now, for the first time, analysed a captive quail population bred from wild-caught animals in search of genetic evidence of the imported Japanese species. The researchers found no genetic admixture in the study population, confirming the success of the breeding programme of the native species. The researchers therefore propose that raising common quails in captivity for restocking purposes rather than domestic Japanese quails or hybrids would be a feasible alternative to minimise the risk of genetic pollution of common quail populations in nature. “The introduction of foreign species may make sense from an economic point of view, but it could have a significant impact on the maintenance of the existing genepool and phenotypic makeup as laboratory studies have shown that the expression of migratory behaviour is strongly reduced among first generation hybrids of Common quail and Japanese quail” explains the project leader, Valeria Marasco. Admixture could especially affect the migratory restlessness of native birds as well as alter other phenotypic traits of the native species.

No genetic influence on European quail from restocking with Japanese relatives

Such changes can be determined using so-called microsatellite markers and mitochondrial DNA analysis. “Microsatellites are repetitive nucleotide sequences throughout the genome that serve as important markers for population and species identification,” says the first author Steve Smith. Mitochondrial DNA is only passed on from the mother. As hybrid quails were mainly produced by crossing female Japanese birds with common quail males, an analysis of mitochondrial DNA can also reveal an admixture of the genepool. Moreover, it can help to determine the natural variance and selection of the genetic material.

Neither analyses revealed any evidence of genetic traces from Japanese quails. “The analysis of the molecular data using various analytic tools clearly showed that the captive animals bred from wild-caught birds were genetically related to the native species. This excludes the domestic Japanese quail as a possible ancestor in the studied captive population in Italy. The results also showed, however, that the variability of the genome of the captive-bred quails was more limited in comparison to that of wild birds. This also represents a potential risk to the wild population and could lead to the introduction of certain alleles, i.e. gene variants, which might cause irreversible changes of the original phenotype”, says Marasco. Despite the possible value of restocking through captive breeding, she recommends a catalogue of measures for the more sustainable regulation of breeding for release purposes. Monitoring should cover not only the introduction of foreign domestic species into the native genepool, but also the possible loss of the natural variance through excessively restrictive breeding measures.

The article „Lack of introgression of Japanese quail in a captive population of common quail“ by Steve Smith, Leonida Fusani, Balint Boglarka, Ines Sanchez-Donoso und Valeria Marasco was published in European Journal of Wildlife Research.