title: Major ecological transitions in wild sunflowers facilitated by hybridization.
abstract: Hybridization is frequent in many organismal groups, but its role in adaptation is poorly understood. In sunflowers, species found in the most extreme habitats are ancient hybrids, and new gene combinations generated by hybridization are speculated to have contributed to ecological divergence. This possibility was tested through phenotypic and genomic comparisons of ancient and synthetic hybrids. Most trait differences in ancient hybrids could be recreated by complementary gene action in synthetic hybrids and were favored by selection. The same combinations of parental chromosomal segments required to generate extreme phenotypes in synthetic hybrids also occurred in ancient hybrids. Thus, hybridization facilitated ecological divergence in sunflowers.
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN 47405, USA. lriesebe@indiana.edu
authors.forename: Loren H
authors.initials: LH
authors.lastname: Rieseberg
authors.forename: Olivier
authors.initials: O
authors.lastname: Raymond
authors.forename: David M
authors.initials: DM
authors.lastname: Rosenthal
authors.forename: Zhao
authors.initials: Z
authors.lastname: Lai
authors.forename: Kevin
authors.initials: K
authors.lastname: Livingstone
authors.forename: Takuya
authors.initials: T
authors.lastname: Nakazato
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Durphy
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Schwarzbach
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Donovan
authors.forename: Christian
authors.initials: C
authors.lastname: Lexer
mesh_terms: D000222:Adaptation, Physiological; D005075:Biological Evolution; D002874:Chromosome Mapping; D004171:Diploidy; D017753:Ecosystem; D004777:Environment; D017343:Genes, Plant; D018745:Genome, Plant; D005838:Genotype; D006368:Helianthus / Q000235:genetics* / Q000502:physiology; D006824:Hybridization, Genetic; D018895:Microsatellite Repeats; D009154:Mutation; D010641:Phenotype; D040641:Quantitative Trait Loci; D012641:Selection, Genetic; D013045:Species Specificity; D014481:United States