ASSORTATIVE FERTILIZATION IN DROSOPHILA

The concept of gametic isolation has its origins in 1937 edition of T. Dobzhansky's Genetics and the Origin of Species. Involving either pos itive assortative fertilization (as opposed to self-incompatibility) o r negative assortative fertilization, it occurs after mating but prior to fertilization. Gametic isolation is generally subsumed under eithe r prezygotic or postmating isolation and thus has not been the subject of extensive investigation. Examples of assortative fertilization in Drosophila are reviewed and compared with those of other organisms. Po tential mechanisms leading to assortative fertilization are discussed, as are their evolutionary implications.