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Revisiting a classic case of introgression: hybridization and gene flow in Californian sunflowers
Author(s) -
Owens Gregory L.,
Baute Gregory J.,
Rieseberg Loren H.
Publication year - 2016
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.13569
Subject(s) - introgression , biology , gene flow , helianthus , evolutionary biology , population , invasive species , species complex , introduced species , botany , ecology , zoology , genetic variation , gene , genetics , phylogenetic tree , sunflower , agronomy , demography , sociology
During invasion, colonizing species can hybridize with native species, potentially swamping out native genomes. However, theory predicts that introgression will often be biased into the invading species. Thus, empirical estimates of gene flow between native and invasive species are important to quantify the actual threat of hybridization with invasive species. One classic example of introgression occurs in California, where Helianthus bolanderi was thought to be a hybrid between the serpentine endemic Helianthus exilis and the congeneric invader Helianthus annuus . We used genotyping by sequencing to look for signals of introgression and population structure. We find that H. bolanderi and H. exilis form one genetic clade, with weak population structure that is associated with geographic location rather than soil composition and likely represent a single species, not two. Additionally, while our results confirmed early molecular analysis and failed to support the hybrid origin of H. bolanderi , we did find evidence for introgression mainly into the invader H. annuus , as predicted by theory.