Article
Nature 423, 715-719 (12 June 2003) | doi:10.1038/nature01679; Received 24 December 2002; Accepted 10 March 2003
Adaptive evolution drives divergence of a hybrid inviability gene between two species of Drosophila
Daven C. Presgraves1, Lakshmi Balagopalan2, Susan M. Abmayr2 and H. Allen Orr1
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 459 North Frear Lab, University Park, Pennsylvania 16802, USA
Correspondence to: Daven C. Presgraves1 Correspondence and requests for materials should be addressed to D.C.P. (Email: dvnp@mail.rochester.edu). Sequences have been deposited in GenBank under accession numbers AY250768–AY250800.
Abstract
Speciation—the splitting of one species into two—occurs by the evolution of any of several forms of reproductive isolation between taxa, including the intrinsic sterility and inviability of hybrids. Abundant evidence shows that these hybrid fitness problems are caused by incompatible interactions between loci: new alleles that become established in one species are sometimes functionally incompatible with alleles at interacting loci from another species. However, almost nothing is known about the genes involved in such hybrid incompatibilities or the evolutionary forces that drive their divergence. Here we identify a gene that causes epistatic inviability in hybrids between two fruitfly species, Drosophila melanogaster and D. simulans. Our population genetic analysis reveals that this gene—which encodes a nuclear pore protein—evolved by positive natural selection in both species' lineages. These results show that a lethal hybrid incompatibility has evolved as a by-product of adaptive protein evolution.