Detection of farm fox and hybrid genotypes among wild arctic foxes in Scandinavia

Abstract

In Scandinavia, farmed arctic foxes frequently escape from farms, raising concern about hybridization with the endangered wild population. This study was performed to find a genetic marker to distinguish escaped farm foxes from wild Scandinavian foxes. Microsatellite and mitochondrial control region variation were analyzed in 41 farm foxes. The results were compared with mitochondrial and microsatellite data from the wild population in Scandinavia. The farm foxes were genetically distinct from the wild foxes (F ST =0.254, P < 0.00001) and all farm foxes had a single control region haplotype different from those observed in the wild population. We developed a method based on Restriction Fragment Length Polymorphism (RFLP) on the mitochondrial control region to differentiate between farmed and wild arctic foxes. This test was subsequently successfully used on 25 samples from free-ranging foxes, of which four had a suspected farm origin. All four of the suspected foxes, and none of the others, carried the farm fox haplotype. Three of these were successfully genotyped for all eleven microsatellite loci. A population assignment test and a Bayesian Markov Chain Monte Carlo analysis indicated that two of these individuals were escaped farm foxes, and that the third possibly was a hybrid between a farmed and a wild arctic fox.

Evolution, ecology and conservation—revisiting three decades of Arctic fox population genetic research

“…Although their origin is quite recent, escaped farm foxes may pose a serious threat to small natural populations through loss of local adaptations and genetic swamping. Hybridization between wild and farmed Arctic foxes was first documented in Iceland (Hersteinsson 1986) and more recently in Scandinavia (Norén et al 2005;Norén, Kvaløy et al 2009). In Iceland, where the Arctic fox population is quite large and robust, there is no known effects of the documented hybridization (Hersteinsson 1986).…”

“…Farmed foxes are genetically divergent from wild, Scandinavian Arctic foxes (Norén et al 2005). Norén, Kvaløy et al (2009) identified a farm fox specific mitochondrial haplotype (termed H9) in 25 out of 182 samples collected across Scandinavia.…”

Farmed arctic foxes on the Fennoscandian mountain tundra: implications for conservation

“…A further potential threat to persistence of Fennoscandian arctic foxes is hybridization between wild and farmed arctic foxes that escape from captivity (Hersteinsson et al, 1989;Linnell et al, 1999;Dal´en et al, 2002;Angerbj¨orn et al, 2004;Andersen et al, 2005;Eide et al, 2005;Nor´en et al, 2005). Commercial production of arctic fox fur was initiated in Alaska at the end of the 19th century.…”

Conspecifics can be aliens too: A review of effects of restocking practices in vertebrates

“…The arctic fox (Alopex lagopus LINNEAUS) is one example, and frequent escapes are of particular concern in Fennoscandia, Randi (2005) where the native arctic fox population currently consists of approximately 150 adults and is classified as endangered (Norén et al 2005). The situation is similar when it comes to the American mink (Neovison vison SCHREBER): farm-raised mink may escape (or be released) and persist in the wild where American mink are endemic (Kidd et al 2009).…”

“…Mating between wild and captive strains of the same species does occur frequently (Kidd et al 2009;Latch et al 2006;Norén et al 2005;Randi 2008), although individuals can sometimes discriminate among them and thus preferentially reproduce with their similes, e.g. in mallard (Cheng et al 1979).…”