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Shifting barriers and phenotypic diversification by hybridisation
Author(s) -
Sefc Kristina M.,
Mattersdorfer Karin,
Ziegelbecker Angelika,
Neuhüttler Nina,
Steiner Oliver,
Goessler Walter,
Koblmüller Stephan
Publication year - 2017
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/ele.12766
Subject(s) - allopatric speciation , biological dispersal , reproductive isolation , biology , assortative mating , ecology , diversification (marketing strategy) , habitat , hybrid zone , evolutionary biology , taxon , ecological speciation , sympatric speciation , littoral zone , mating , genetic variation , population , marketing , sociology , business , gene flow , biochemistry , demography , gene
The establishment of hybrid taxa relies on reproductive isolation from the parental forms, typically achieved by ecological differentiation. Here, we present an alternative mechanism, in which shifts in the strength and location of dispersal barriers facilitate diversification by hybridisation. Our case study concerns the highly diverse, stenotopic rock‐dwelling cichlids of the African Great Lakes, many of which display geographic colour pattern variation. The littoral habitat of these fish has repeatedly been restructured in the course of ancient lake level fluctuations. Genetic data and an experimental cross support the hybrid origin of a distinct yellow‐coloured variant of Tropheus moorii from ancient admixture between two allopatric, red and bluish variants. Deficient assortative mating preferences imply that reproductive isolation continues to be contingent on geographic separation. Linking paleolimnological data with the establishment of the hybrid variant, we sketch a selectively neutral diversification process governed solely by rearrangements of dispersal barriers.