For decades, studies of rapid species radiations have provided insight into the processes that drive biological diversification, but recently these analyses have been revolutionized by data from next-generation sequencing technologies.
Using transcriptomic, genomic, and genetic mapping analyses, we are dissecting the mechanisms underlying the recent rapid evolution of floral (and other) trait diversity among species in the plant genus Jaltomata. Although this genus is less than 5 million years old, the estimated 60-80 species of Jaltomata show a remarkable and unique diversity of newly evolved floral traits, especially in corolla (petal) shapes—including rotate, bell-shaped, and tubular forms—and in the amount and color of nectar they produce, which ranges from small amounts of nectar that is essentially colorless to copious amounts of deep red nectar.
Our transcriptome and genomic analyses indicate that de novo adaptive mutation, selection from standing genetic variation, and gene duplication of development loci, are all potential sources of adaptive genetic variation for this novel trait evolution. Quantitative trait analysis indicates that several important floral transitions are based on largely additive effects at a few to moderate number of loci. Together, these data suggest that rapid floral evolution could have been facilitated by a relatively simple genetic architecture that drew from a diverse pool of genetic variation.