http://www.ncbi.nlm.nih.gov/pubmed/24050727

The topic of polecat back-breeding on domestic ferrets in relation to
health and behavior has often been discussed, but this paper is on
the hypothesis of reduced viability of polecats due to the influx of
genetics from feral ferrets -- which would have been mostly hunting
ferrets at that time -- in the UK in the nineteenth century which was
a time when polecats also were being actively destroyed by people,
creating a genetic bottleneck. The hypothesis did not consistently pan
out in relation to the bottleneck, but a high influx of ferret genetics
was found except in Wales.

QUOTED ABSTRACT:

Mol Ecol. 2013 Sep 17. doi: 10.1111/mec.12456. [Epub ahead of print]
The genetic legacy of the 19th-century decline of the British polecat:
evidence for extensive introgression from feral ferrets.

Costa M, Fernandes C, Birks JD, Kitchener AC, Santos-Reis M, Bruford MW.

Source
Centro de Biologia Ambiental, Faculdade de Ciencias da Universidade de
Lisboa, Edificio C2, 5 Piso, Campo Grande, 1749-016, Lisboa, Portugal;
OnE - Organisms and Environment Division, School of Biosciences,
Cardiff University, Sir Martin Evans Building, Cardiff, CF10 3AX, UK.

Abstract
In the 19th century, the British polecat suffered a demographic
contraction, as a consequence of direct persecution, reaching its
lowest population in the years that preceded the First World War.
The polecat is now recovering and expanding throughout Britain, but
introgressive hybridization with feral ferrets has been reported, which
could be masking the true range of the polecat and introducing domestic
genes into the species. We used a fragment of the mitochondrial DNA
control region and 11 microsatellite loci to characterize the frequency
and extent of hybridization and introgression between the two species
and assess whether the 19th-century decline corresponded to a genetic
bottleneck in the polecat. The proportion of admixture detected in the
wild was high (31%) and hybrids were more frequently found outside
Wales, suggesting that hybridization is more likely to occur along the
eastern edge of the polecat's range expansion. The patterns observed
in the mitochondrial and nuclear DNA data show that introgression was
mediated by crosses between male polecats and female ferrets, whose
offspring backcrossed with polecats. No first-generation (F1 ) hybrids
were identified, and the broad range of observed admixture proportions
agrees with a scenario of past extensive hybridization between the two
species. Using several different methods to investigate demographic
history, we did not find consistent evidence for a genetic bottleneck
in the British polecat, a result that could be interpreted as a
consequence of hybridization with ferrets. Our results highlight the
importance of the Welsh polecat population for the conservation and
restoration of the genetic identity of the British polecat.
(c) 2013 John Wiley & Sons Ltd.

KEYWORDS:
Mustela furo , Mustela putorius , Britain, European polecat,
hybridization, microsatellites
PMID: 24050727 [PubMed - as supplied by publisher]

[Posted in FML 7913]