A comparison of microsatellites and genome‐wide SNPs for the detection of admixture brings the first molecular evidence for hybridization between Mustela eversmanii and M. putorius (Mustelidae, Carnivora)

Abstract

Introgressive hybridization can pose a serious threat to endangered species which have an overlapping distribution such as in the case of two polecat species, Mustela eversmanii and M. putorius, in Europe. The population size of steppe polecat is known to continuously shrink, whereas its sister species, the European polecat, is still somehow widespread. In this study, we perform an analysis using microsatellite (SSR) and genomic (SNP) data sets to identify natural hybrids between polecats. Four populations were genotyped for eight polymorphic SSR loci, and thousands of unlinked SNPs were generated using a reduced‐representation sequencing approach, RADseq, to characterize the genetic make‐up of allopatric populations and to identify hybrids in the sympatric area. We applied standard population genetic analyses to characterize the populations based on their SSR allelic frequency. Only a single sample out of 48 sympatric samples showed exact intermediacy that we identified as an F1 hybrid. Additionally, one specimen was indicated in the genomic data sets as backcrossed. Other backcrosses, indicated by SSRs, were not validated by SNPs, which highlights the higher efficacy of the genomic method to identify backcrossed individuals. The low frequency of hybridization suggests that the difference in habitat preference of the two species may act as a barrier to admixture. Therefore, it is apparently unlikely that polecat populations are threatened by significant introgression. The two species showed a clear genetic differentiation using both techniques. We found higher genetic diversity values in the sympatric steppe polecat population than in the other studies on polecat populations. Although M. putorius is a hunted species in most countries, genetic diversity values indicate worse conditions in Europe than in the protected sibling species M. eversmanii. Suspending hunting and providing protected status of the former seems to be reasonable and timely.

Extensive genome introgression between domestic ferret and European polecat during population recovery in Great Britain

“…We also see evidence of introgression between European polecat and Steppe polecat ( Fig. 4 ), supporting further evidence of hybridization between the 2 species, but it should be noted that the origin of Steppe polecats used in this work (Inner Mongolia) is well beyond the sympatric range overlap with European polecats that earlier work has studied ( Cserkész et al 2021 ; Szatmari et al 2021 ), suggesting the possibility of widespread introgression.…”

“…Blandford and Walton 1991 ; Driscoll et al 2009 ), or their findings being inconclusive between the 2 potential ancestral species ( Davison et al 1999 ; Kurose et al 2008 ). European polecats are known to hybridize with a number of other mustelid species, including Steppe polecat ( Cserkész et al 2021 ; Szatmari et al 2021 ), European Mink ( Lode et al 2005 ; Cabria et al 2011 ), and domestic ferret ( Davison et al 1999 ; Costa et al 2012 ).…”

Relictual Hybridization and Biogeography of Massasauga Rattlesnakes (Sistrurusspp.)

“…In this study, genetic signatures of historic admixture were clearly detected in the Missouri populations, due largely to the greater capacity of SNP data to diagnose evolutionary and demographic processes at deeper time scales (Morin et al, 2004; Haasl and Payseur, 2011; Lee et al, 2018; Chafin et al, 2021). In addition, numerous studies have validated the enhanced capacity of SNPs to diagnose hybridity, particularly when compared with microsatellite loci (CamachoLSanchez et al, 2020; Sunde et al, 2020; Zimmerman et al, 2020; Szatmári et al, 2021). This is largely because microsatellite alleles are highly variable, with substantial homoplasy, and are thus rarely diagnostic (Estoup et al, 2000, and references therein).…”

Long‐term translocation explains population genetic structure of a recreationally fished iconic species in Japan: Combining current knowledge with reanalysis

“…Hybridisation and hybrid individuals in contact zones can be identified by Bayesian clustering methods using highly polymorphic molecular markers such as microsatellites (Beaumont et al., 2001; Manel et al., 2005; Pierpaoli et al., 2003; Vähä & Primmer, 2006). In admixture analyses, a threshold for an individual admixture coefficient ( q ‐value) inferred from STRUCTURE is generally used to identify hybrid individuals (Szatmári et al., 2021). A low threshold q ‐value of 0.1 (10%) was efficient for detecting hybrids between two distinct purebred classes or different species (Vähä & Primmer, 2006) and proved highly effective results in such empirical cases of various species (Devitt et al., 2011; Fogelqvist et al., 2015; Szatmári et al., 2021; van Wyk et al., 2017).…”

“…In admixture analyses, a threshold for an individual admixture coefficient ( q ‐value) inferred from STRUCTURE is generally used to identify hybrid individuals (Szatmári et al., 2021). A low threshold q ‐value of 0.1 (10%) was efficient for detecting hybrids between two distinct purebred classes or different species (Vähä & Primmer, 2006) and proved highly effective results in such empirical cases of various species (Devitt et al., 2011; Fogelqvist et al., 2015; Szatmári et al., 2021; van Wyk et al., 2017). Contrarily, the present study aims to estimate hybrids between landlocked and amphidromous forms of Ayu, which would be genetically closer than between two distinct purebred classes or different species; a 0.2 (20%) threshold q ‐value is used herein, where individuals with landlocked ancestral genes (0.8 > q > 0.2) are classified as hybrids, those with q ≥ 0.8 as the original landlocked form, and those for which q ≤ 0.2 as the original amphidromous form (Geraldes et al 2014; Karamanlidis et al 2021; Larison et al 2021).…”