Mechanisms of Speciation - A Population Genetic Approach
In his review of White's book on Modes of Speciation, Sewall Wright (249) stated, least adequate aspect of 'Modes of Speciation' is the absence of systematic discussion of speciation as a process by which reproductive isolation of a whole population traces to genetic phenomena at the level of the individual. The investigation of such processes is the subject of population genetics. Serious consideration requires mathematical analysis and experiments as well as consideration of the results of speciation to which most attention is paid. The purpose of this review is to initiate the discussion absent in White's (234) book and much of the speciation literature. I begin with a brief survey of what descriptive population genetics has revealed about the results of speciation. Next, I present a population-genetic classification of modes of speciation followed by a discussion of how theoretical, experimental, and descriptive population-genetic studies can be related to each of the modes. Finally, I discuss the possible relative importance of these modes and outline why it is important for population genetics and speciation theory to become integrated.