Hybridization leads to interspecific gene flow in Sarracenia (Sarraceniaceae)

The role of hybridization in plant evolution remains a source of intense debate. Potential consequences range from genetic dead-ends to species fusion or hybrid speciation. While much has been learned from model systems such as Populus, Iris, and Helianthus, many questions remain. Consisting of 11 species that are all capable of hybridizing, Sarracenia presents an excellent system in which to study hybridization. •

Using microsatellites, we examined a single field site consisting of three species: S. leucophylla, S. alata, and S. rubra subsp. wherryi. We determined the level of genetic admixture and compared it with allopatric sites of the same taxa. •

In contrast to the well-defined clusters formed when we examined the allopatric sites, the sympatric field site exhibited a wide range of admixture. Additionally, when the relative genetic makeup of "pure" species at the site was compared with the makeup of hybrids, we found that Sarracenia alata contributed disproportionately to the hybrid genomes. •

Our study provides further evidence that hybridization is contributing to interspecific gene flow in the genus and that all species do not contribute equally to hybridization. Implications for conservation are discussed.