Multilocus analyses indicate a mosaic distribution of hybrid populations in ground squirrels (genusIctidomys)

Abstract

DNA sequence data from mitochondrial cytochrome-b (Cytb) and Y-linked structural maintenance of chromosomes (SmcY) genes were combined with 478 nuclear loci obtained from amplified fragment length polymorphisms (AFLP) to assess the extent of hybridization and genetic spatial structure of populations in two hybridizing species of ground squirrel (Ictidomys parvidens and Ictidomys tridecemlineatus). Based on AFLP analyses of 134 individuals from 28 populations, 10 populations were identified that possessed hybrid individuals. Overall estimates of FST values revealed strong support for population structure in the Cytb data set; however, analyses of the SmcY gene and the AFLP data indicated ongoing gene flow between species. Pairwise FST comparisons of populations were not significant for the SmcY gene; although they were significant for the Cytb gene, indicating that these populations were structured and that gene flow was minimal. Therefore, gene flow between I. parvidens and I. tridecemlineatus appeared to be restricted to populations that exhibited hybridization. In addition, the fragmented nature of the geographic landscape suggested limited gene flow between populations. As a result, the distributional pattern of interspersed parental and hybrid populations were compatible with a mosaic hybrid zone model. Because ground squirrels display female philopatry and male-biased dispersal, the ecology of these species is compatible with this hypothesis.

A Study of Hybridization Between Marmota baibacina and M. sibirica in Their Secondary Contact Zone in Mongolian Altai

“…Revealing ancient hybridization in different taxa also broadens understanding of the contribution of hybridization to mammalian evolution (e.g., Marques et al, 2017). In the ground squirrels Marmotini up to a quarter of species are involved in hybridization events of varying intensity, from sporadic hybridization to the formation of hybrid zones and wide introgression according to our estimates of the literature data (Semenova, 1967;Nikol'skii et al, 1983;Smirin et al, 1985;Good et al, 2008;Stangl et al, 2012;Thompson et al, 2013;Ermakov et al, 2015;Frare et al, 2017;Ivanova et al, 2017;Leitner et al, 2017;Kapustina et al, 2018).…”

Rapid molecular species identification of mammalian scat samples using nanopore adaptive sampling

“…In line with previous studies focused on mitochondrial based species identifications, as well as critiques of such methods, extra caution must be used when considering incomplete lineage sorting, mitochondrial capture, and historical or active hybrid zones (Larsen et al 2010;Thompson et al 2013;vonHoldt et al 2016). In certain situations, using NAS for species identification may require extra care, for example when distinguishing particular wild species and their domestic counterparts (e.g., polecat and domestic ferret, wildcat and domestic cat, wolf, and domestic dog).…”

Environmental (in)dependence of a hybrid zone: Insights from molecular markers and ecological niche modeling in a hybrid zone ofOriganum(Lamiaceae) on the island of Crete

“…This hybrid zone was initially analyzed with respect to the genetic structure of populations using the AFLP technique which provides a variety of polymorphic markers derived from total DNA (Vos et al., ) and has been proven useful in the characterization of parental and hybrid genotypes (e.g., Eidesen, Alsos, & Brochmann, ; Galbany‐Casals, Carnicero‐Campmany, Blanco‐Moreno, & Smissen, ; Georgescu, Stefanakis, Kokkini, Katerinopoulos, & Pirintsos, ; Thompson, Anwarali Khan, Stangl, Baker, & Bradley, ; Zeng, Liao, Petit, & Zhang, ). The analysis of the polymorphic dominant markers revealed only five markers exhibiting substantial frequency differences among the parental taxa for both allopatric and sympatric populations.…”

“…The analysis of the polymorphic dominant markers revealed only five markers exhibiting substantial frequency differences among the parental taxa for both allopatric and sympatric populations. The identification of few species‐specific markers has been documented in other studies of interspecific hybridization, where AFLP markers have been used (Minder Rothenbuhler, & Widmer, ; Thompson et al., ; Wu & Campbell, ) indicating weak genetic differentiation across the genome in species under hybridization. Nevertheless, those species‐specific markers may be important for the maintenance even of a minimum degree of genetic differentiation preserving species integrity.…”