Molecular Origin of Species

摘要

In sexually reproducing organisms, new species originate when a reproductive barrier is established between different groups of organisms. This event, called speciation, is one of the most important biological processes, yet its mechanism remains largely unknown. Reproductive isolation between species can occur either before or after the formation of hybrid zy-gotes. In prezygotic isolation, mating or fertilization is prevented, whereas postzygotic isolation occurs by the sterility or inviability of the hybrid offspring.