"The role of hybridization in adaptive evolution is contentious. While many cases of adaptive trait introgression have been proposed, the relevant traits have rarely been identified, resulting in a lack of clear examples of this process," write the authors.
The researchers examined a northern sunflower species that had captured genes from a southern sunflower species, resulting in a stabilized hybrid, Helianthus annuus texanus, able to expand southward into central and southern Texas. They then recreated the original hybridization event by manually crossing two parent species. Not only were these hybrids resistant to the insects that attack sunflowers, they also produced more seeds than the uncrossed plants.
"The results show for the first time that adaptive trait introgression can be a potent evolutionary force, broadening our view of the mechanisms by which populations adapt to their environments," explain the authors.
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Kenneth D. Whitney, Rebecca A. Randell, and Loren H. Rieseberg. "Adaptive introgression of herbivore resistance to traits in the weedy sunflower Helianthus," The American Naturalist 167:6.