Recent advances in assessing gene flow between diverging populations and species.

The evolutionary process of divergence, which ultimately leads to the generation of new species, is thought to occur usually without any gene exchange between the diverging populations. However, until the recent growth of multi-locus datasets, and the development of new population genetic methods, it has been very difficult to assess whether or not closely related species have, or have not, exchanged genes during their divergence. Several recent studies have found significant signals of gene flow during species formation, calling into question the conventional wisdom that gene flow is absent during speciation.