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Divergent population structure and climate associations of a chromosomal inversion polymorphism across the M imulus guttatus species complex
Author(s) -
Oneal Elen,
Lowry David B.,
Wright Kevin M.,
Zhu Zhirui,
Willis John H.
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12778
Subject(s) - biology , ecotype , gene flow , local adaptation , reproductive isolation , evolutionary biology , species complex , population , demographic history , population genomics , ecology , genetic divergence , genetic diversity , genetic variation , genome , genetics , genomics , gene , phylogenetic tree , demography , sociology
Chromosomal rearrangement polymorphisms are common and increasingly found to be associated with adaptive ecological divergence and speciation. Rearrangements, such as inversions, reduce recombination in heterozygous individuals and thus can protect favourable allelic combinations at linked loci, facilitating their spread in the presence of gene flow. Recently, we identified a chromosomal inversion polymorphism that contributes to ecological adaptation and reproductive isolation between annual and perennial ecotypes of the yellow monkeyflower, M imulus guttatus . Here we evaluate the population genetic structure of this inverted region in comparison with the collinear regions of the genome across the M . guttatus species complex. We tested whether annual and perennial M . guttatus exhibit different patterns of divergence for loci in the inverted and noninverted regions of the genome. We then evaluated whether there are contrasting climate associations with these genomic regions through redundancy analysis. We found that the inversion exhibits broadly different patterns of divergence among annual and perennial M . guttatus and is associated with environmental variation across population accessions. This study is the first widespread population genetic survey of the diversity of the M . guttatus species complex. Our findings contribute to a greater understanding of morphological, ecological, and genetic evolutionary divergence across this highly diverse group of closely related ecotypes and species. Finally, understanding species relationships among M . guttatus sp. has hitherto been stymied by accumulated evidence of substantial gene flow among populations as well as designated species. Nevertheless, our results shed light on these relationships and provide insight into adaptation in life history traits within the complex.