recent advances in molecular genetics have made it clear that new plant species can evolve via two or more mutational steps, as is predicted by the Dobzhansky-Muller model. F1000 Report by Andrea L. Sweigart and John H. Willis <http://p4trc.emv2.com/HS?a=ENX7CqkWrP9- 8SA9M KJatd3nGHxKLTN8EPcStGb5lw8W0b8hOG5mpqVsj