RPM points out that the most recent issue of Heredity tackles the issue of the genetics of speciation. Here’s an interesting thing I’ve noted, there are two ways to look at species questions. First, there are the taxonomists, who have been strongly influenced by the cladist revolution. They take a big picture philosophical view, and are obviously greatly concerned with process in terms of classification and demarcation. In contrast, there are the evolutionary geneticists who tend to be less interested in species qua species, as opposed to the process of genetic differentiation. In other words, for the latter camp species discussions are simply an ends toward elucidating the evolutionary dynamics of populations. The taxonomists in contrast are focused on species as the ends for generating their systems of evolutionary relationships. The Neandertal introgression story should make it clear I’m interested in the dynamics of evolutionary processes, not any rigorous species classification.
Addendum: Check out this review of Henry Gee’s In Search of Deep Time: Beyond the Fossil Record to a New History of Life, to see what I mean about the taxonomic sensibility. A friend of mine recalls observing a woman in her lab being upbraided by a cladist at an entomological conference for practicing “un-Popperian” science.