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A comparative analysis of the mechanisms underlying speciation on Lord Howe Island
Author(s) -
Papadopulos A. S. T.,
Price Z.,
Devaux C.,
Hipperson H.,
Smadja C. M.,
Hutton I.,
Baker W. J.,
Butlin R. K.,
Savolainen V.
Publication year - 2013
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.12071
Subject(s) - biology , ecological speciation , genetic algorithm , evolutionary biology , ecological niche , ecology , adaptive radiation , adaptation (eye) , genetic divergence , natural selection , population , local adaptation , taxon , phylogenetic tree , gene flow , genetic diversity , genetic variation , genetics , habitat , gene , demography , neuroscience , sociology
On Lord Howe Island, speciation is thought to have taken place in situ in a diverse array of distantly related plant taxa ( Metrosideros , Howea and Coprosma ; Proc. Natl Acad. Sci. USA 108 , 2011, 13188). We now investigate whether the speciation processes were driven by divergent natural selection in each genus by examining the extent of ecological and genetic divergence. We present new and extensive, ecological and genetic data for all three genera. Consistent with ecologically driven speciation, outlier loci were detected using genome scan methods. This mechanism is supported by individual‐based analyses of genotype–environment correlations within species, demonstrating that local adaptation is currently widespread on the island. Genetic analyses show that prezygotic isolating barriers within species are currently insufficiently strong to allow further population differentiation. Interspecific hybridization was found in both Howea and Coprosma , and species distribution modelling indicates that competitive exclusion may result in selection against admixed individuals. Colonization of new niches, partly fuelled by the rapid generation of new adaptive genotypes via hybridization, appears to have resulted in the adaptive radiation in Coprosma – supporting the ‘Syngameon hypothesis’.