Evidence of neutral and adaptive genetic divergence between European trout populations sampled along altitudinal gradients

Keller, I.; Taverna, A.; Seehausen, O. (2011). Evidence of neutral and adaptive genetic divergence between European trout populations sampled along altitudinal gradients. Molecular Ecology, 20(9), pp. 1888-1904. Oxford: Wiley-Blackwell 10.1111/j.1365-294X.2011.05067.x

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Species with a wide geographical distribution are often composed of distinct subgroups which may be adapted to their local environment. European trout (Salmo trutta species complex) provide an example of such a complex consisting of several genetically and ecologically distinct forms. However, trout populations are strongly influenced by human activities, and it is unclear to what extent neutral and adaptive genetic differences have persisted. We sampled 30 Swiss trout populations from heterogeneous environments along replicated altitudinal gradients in three major European drainages. More than 850 individuals were genotyped at 18 microsatellite loci which included loci diagnostic for evolutionary lineages and candidate markers associated with temperature tolerance, reproductive timing and immune defence. We find that the phylogeographic structure of Swiss trout populations has not been completely erased by stocking. Distinct genetic clusters corresponding to the different drainages could be identified, although nonindigenous alleles were clearly present, especially in the two Mediterranean drainages. We also still detected neutral genetic differentiation within rivers which was often associated with the geographical distance between populations. Five loci showed evidence of divergent selection between populations with several drainage-specific patterns. Lineage-diagnostic markers, a marker linked to a quantitative trait locus for upper temperature tolerance in other salmonids and a marker linked to the major histocompatibility class I gene were implicated in local adaptation and some patterns were associated with altitude. In contrast, tentative evidence suggests a signal of balancing selection at a second immune relevant gene (TAP2). Our results confirm the persistence of both neutral and potentially adaptive genetic differences between trout populations in the face of massive human-mediated dispersal.

Item Type:	Journal Article (Original Article)
Division/Institute:	08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology
UniBE Contributor:	Seehausen, Ole
ISSN:	0962-1083
Publisher:	Wiley-Blackwell
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:27
Last Modified:	05 Dec 2022 14:08
Publisher DOI:	10.1111/j.1365-294X.2011.05067.x
Web of Science ID:	000289522400011
URI:	https://boris.unibe.ch/id/eprint/10109 (FactScience: 215949)