Hybridization: the sum of the whole, etc.

Individual point mutations in DNA provide a mechanism by which organisms evolve altered proteins that can prove to be advantageous. However, this explanation for the successful adaptation of an organism to a novel environment is problematic, as colonization of specific niches should require multiple gene interactions that are unlikely to occur by single sequential genetic alterations. In the August 7 Sciencexpress, Loren Rieseberg and colleagues at Indiana University investigate the effect of hybridization in sunflowers as a means of providing variation that incorporates both the multigene requirement and the rapid acquisition of successful traits for adaptation to extreme environments (Sciencexpress, DOI:10.1126/science.1086949, August 7, 2003).

Rieseberg et al. investigated three species of Helianthus (H. anomalus, H. deserticola, and H. paradoxus) that exist in arid, desert, and salt marsh environments and that are derived from hybridization of two common and widespread species, H. annus and H. petiolaris. They...