Our program’s strengths involve our research on the two fundamental evolutionary processes: speciation and adaptation. Our faculty, postdoctoral fellows, and graduate students investigate these two core topics using field studies, lab work, computational biology and theory, with genetics as unifying theme.
Our program has a history of leadership in speciation research, thanks largely to the successful application of cutting-edge genetic tools to ages old questions. A number of laboratories are working to reveal the precise genetic basis for speciation and species differences. Research in the Orr and Presgraves laboratories, for example, has identified four of the ten ‘speciation genes’ that are known to act as barriers to successful reproduction between closely related species of Drosophila. The Werren and Jaenike labs, meanwhile, have played a central role in the surprising discovery that intracellular parasites can be important to speciation by resulting in reproductive isolation between their host species. In addition to demonstrating the importance of the widespread intracellular parasite Wolbachia to postzygotic isolation, work in the Jaenike Lab has shown that Wolbachia can even cause the evolution of behavioral isolation in natural populations. The Fry Lab has also contributed to our understanding of speciation theory. The Garrigan Lab develops new computational and statistical methods to make inferences about the history of speciation events, especially in Drosophila and in humans, using large-scale population genomic data. The Rabeling lab studies the sympatric origins of new ant species.
Darwin’s most important insight was that natural selection is the engine of adaptation and biological diversification. Our group studies the genetic basis of adaptation in the lab (Fry, Werren, Orr, Brisson), as well as theoretical aspects adaptation (Orr). The Fry Lab uses the genetic tools of Drosophila melanogaster to dissect the molecular basis of ethanol resistance in the wild. The Werren Lab has developed new genomic resources in species of Nasonia parasitic wasps to study the genetic and developmental basis of species differences in morphology. The Jaenike Lab studies the ecology, population dynamics, and geographical spread of a maternally transmitted endosymbiont (Spiroplasma) that confers resistance to nematodes that parasitize Drosophila. The Lambert Lab uses the marine snail, Ilyanassa, as a model system to study the evolution of novel mechanisms of embryonic development. The Brisson Lab studies the molecular genetic basis of winged and wingless morphs of aphids. The Orr Lab has also made seminal contributions to our understanding of the population genetics of adaptation.
Our program has long been at the forefront of work on the evolution and consequences of the selfish genetic elements that parasitize genomes. The Eickbush Lab, for example, has played an important role in understanding how mobile selfish DNA elements evolve and persist in host genomes. The Werren Lab has been a leader in the study selfish genes, from the wide-ranging intracellular parasite, Wolbachia, to repetitive DNAs, to the ultra-selfish B-chromosome of Nasonia. The Larracuente lab studies the evolutionary and functional genomics of satellite DNA— large arrays of tandemly repeated sequences that can make up a huge fraction of eukaryotic genomes. Work in the Jaenike, Presgraves and Larracuente Labs focus on the evolutionary genetics of selfish segregation distorter chromosomes in Drosophila. Allen Orr’s lab recently discovered that a segregation disorter gene contributes to speciation between two young Drosophila species.