April 10 2019

12:00 LSB 2320

Ken Whitney
Department of Biology, University of New Mexico

Can Hybridization Speed Adaptation? Experimental Evolution in Sunflowers Can Hybridization Speed Adaptation? Experimental Evolution in Sunflowers


Hybridization is a common phenomenon, yet its evolutionary outcomes remain debated. Here, we ask whether hybridization can speed adaptive evolution using hybrids between two species of Texas sunflowers (Helianthus annuus and H. debilis). We established separate control and hybrid populations and allowed them to evolve naturally in a field evolutionary experiment. In a final common-garden, we measured fitness and a suite of key traits for these lineages. We show that hybrid fitness evolved in just eight generations, with fitness of the hybrid lines exceeding that of the controls by 14% and 51% by the end of the experiment. More traits evolved significantly in hybrids relative to controls, and hybrid evolution was faster for most traits. Some traits in both lineages evolved in an adaptive manner consistent with the direction of phenotypic selection. These findings show a causal pathway from hybridization to rapid adaptation and suggest an explanation for the frequently noted association between hybridization and adaptive radiation, range expansion, and invasion.

Host: Tom Smith











































































































































































































































































































































































































































































































































































































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