Type, and Location on the Performance of Parental and Hybrid Big Sagebrush Reciprocal Transplants in the Gardens of

Abstract: The majority of flowering plant species are descendent from hybridization events; therefore, understanding hybridization in nature is essential to understanding plant speciation. Hybrid zones, common and often stable, provide one source of hybridiza-tion. Stable hybrid zones are particularly important in evolutionary theory because they violate adaptive speciation theory and call into question the universality of reproductive isolation in speciation. Under this model, hybrids are assumed to be unfit regardless of environment, due to endogenous selection, thereby contributing to reproductive isolation. However, a number of stable hybrid zones show hybrids to be most fit within the hybrid zone due to ecological selection. Regardless of the type of selection occurring, stability of the hybrid zone results from a balance between gene flow and selection. What is not known is how hybridization allows hybrids to become adapted to the habitat of the hybrid zone. An understandin