Widespread introgression of mountain hare genes into Fennoscandian brown hare populations

Abstract

In Fennoscandia, mountain hare (Lepus timidus) and brown hare (Lepus europaeus) hybridize and produce fertile offspring, resulting in gene flow across the species barrier. Analyses of maternally inherited mitochondrial DNA (mtDNA) show that introgression occur frequently, but unavailability of appropriate nuclear DNA markers has made it difficult to evaluate the scale- and significance for the species. The extent of introgression has become important as the brown hare is continuously expanding its range northward, at the apparent expense of the mountain hare, raising concerns about possible competition. We report here, based on analysis of 6833 SNP markers, that the introgression is highly asymmetrical in the direction of gene flow from mountain hare to brown hare, and that the levels of nuclear gene introgression are independent of mtDNA introgression. While it is possible that brown hares obtain locally adapted alleles from the resident mountain hares, the low levels of mountain hare alleles among allopatric brown hares suggest that hybridization is driven by stochastic processes. Interspecific geneflow with the brown hare is unlikely to have major impacts on mountain hare in Fennoscandia, but direct competition may.

Identification of hybridization and introgression between Cinnamomum kanehirae Hayata and C. camphora (L.) Presl using genotyping-by-sequencing

“…Thus, for the best delta K, individuals with Q-values between 0.1 and 0.9 were considered to be hybrids or backcrosses, while individuals with Q-values ≥ 0.9 were considered to be pure species. This coincides with previous studies 2,17,53,54 . NewHybrids was used to classify individuals as pure parent species, F1s, F2s or backcrosses.…”

“…Our data are of relevance because the C. kanehirae wood has high market value for use in culturing A. cinnamomea. Although hybrids might be useful in breeding programs and may outcompete the parent species 17,42 , the experimental evaluation of hybrid wood quality is still necessary in the future to ensure the alternative utilization of the hybrids. Therefore, from the conservation point of view, before the evaluation of the effects in the hybrid population, it is better to limit the dispersal of the hybrids in the nursery.…”

“…In the aspect of management, the putative hybrids will lead to worrisome issues that may spoil pure C. kanehirae and affect the genetic pool of the natural populations of C. camphora and C. kanehirae . Moreover, hybridization may lead to genetic swamping, where hybrids overwhelm or outcompete the rarer parent species 17 . To avoid the loss of C. kanehirae genetic diversity and the misuse of hybrid woods, it is very important to further understand hybrids between these two species in the wild.…”

Hare's affairs: Lessons learnt from a noninvasive genetic monitoring for tracking mountain hare individuals

“…Furthermore, hybridization between the two species could lead to introgression and threaten the genetic integrity of the mountain hare (Thulin, 2003; Thulin, Fang, & Averianov, 2006). Recent hybridization has been well documented in Scandinavia (e.g., Levänen, Thulin, Spong, & Pohjoismaki, 2018), whereas the current patterns of hybridization in the Alps are largely unknown (Beugin et al., 2017; Zachos, Slimen, Hacklander, Giacometti, & Suchentrunk, 2010). To understand the threats mountain hare populations are facing in the Alps, it is thus essential to monitor the occurrence of European hares and hybrids, in particular where species' elevational ranges overlap.…”

Large-scale mitochondrial DNA analysis reveals new light on the phylogeography of Central and Eastern-European Brown hare (Lepus europaeus Pallas, 1778)

“…europaeus only in one sample (GER4 in S1 Table ) from Germany ( Fig 6 ). Extensive introgression mtDNA and nuclear genes of mountain hare into other hares has been reported in previous studies (e.g., [ 47 – 48 ]). The introgression of individual genotypes among populations potentially could have resulted from recent genetic hybridization or incomplete lineage sorting of ancestral variation.…”