This research sheds some interesting light on the early stages of speciation – the divergence of one species into two. At these stages, the species are mostly separate from each other, but a limited amount of interbreeding, and thus gene transfer, still takes place; not necessarily enough to make the two species converge back into one (especially if they are specialised towards different ecological niches), but enough to have a non-trivial impact on the genetic diversity of both species. Whether the speciation continues to the point hybridisation incurs too much of a fitness cost and the species diverge to become irreversibly distinct, or whether they converge back into a single species, seems to depend very strongly on environmental factors; this process is apparently rather fluid.