Ian M. Dworkin
Ph.D., University of Toronto, 2004
Phenotypic Variation and Evolution
What is the genetic basis of divergence, and adaptive differentiation, and how does the current distribution of genotypes in a population influence future evolutionary responses? Broadly speaking our lab uses genetic and genomic approaches to study the evolution of complex traits, including developmental, morphological and behavioural phenotypes. While the work in the lab is primarily done using the fruit fly Drosophila melanogaster (and closely related species), in collaboration with other labs we utilize a wide variety of organisms to address these questions. Currently we are addressing several broad questions in evolutionary genetics.
First we are dissecting the genetic architecture of wing shape in Drosophila, using a combination of genetic and genomic approaches, both within and between closely related species. In conjunction with these studies of natural genetic variation we utilize induced mutations and engineered strains to carefully control the function of candidate genes that play a role in wing shape to address how variation in expression influences both the magnitude and direction of effects. Our work, in conjunction with our collaborators will hopefully allow us to partially predict the genetic basis of the response to selection. Second we are investigating conditional effects of mutations, both naturally occurring and induced. We examine these conditional allelic effects with respect to changes in the overall genotype (often described as genetic background effects), the external environment (such as rearing temperature and density), and their interaction. Currently we are testing the effects of sets of alleles that vary in their phenotypic effects on wing size and shape across a range of genetic backgrounds and environmental conditions. In addition we are mapping some of these naturally occurring genetic background modifiers, to test both their function and to examine their pleiotropic consequences in natural and experimental populations.
Finally we have recently begun a long term experimental evolutionary approach to the study of how animals avoid being preyed upon (anti-predation behaviour and traits). We have begun to examine whether traits like wing shape may be targets of natural selection for predator escape, and how these traits in experimental evolutionary conditions. In addition we are using genetic approaches to study the behavioural component of the anti-predation response. With respect to all of the projects in the lab we not only developing experimental systems to test sets of explicit evolutionary questions, but we are engaged with developing and implementing statistical approaches for testing these models.
Chandler, C.H., Chari, S. & Dworkin, I. (2013). does your gene need a background check? How genetic background impacts the analysis of mutations, genes, and evolution. Trends in Genetics. In Press. http://dx.doi.org/10.1016/j.tig.2013.01.009
Chandler, C.H. Ofria, C. & Dworkin, I. (2013) Runaway Sexual Selection leads to Good Genes. Evolution. 67(1): 110-119. doi:10.111/j.1558-5646.2012.01750.x
Pitchers, W.R., Pool, J. & Dworkin, I. (2013). Altitudinal Clinal Variation in Wing Form in African Drosophila melanogaster: One Cline or Many? Evolution. 67(2): 438-452 doi: 10.111/j.1558-5646.2012.01774.x
Emlen, D.J., Warren, I., Johns, A., Dworkin, I. & Corley-Lavine, L. (2012). A mechanism of extreme growth and reliable signaling in sexually selected ornaments and weapons. Science. 337:860-864. doi:10.1126/science.1224286
Dworkin, I., Anderson, J.B., Idaghdour, Y., Parker, E.K., Stone, E.A., & Gibson, G. (2011). The Effects of Weak Genetic Perturbations on the Transcriptome of the Wing Imaginal Disc, and its Association with Wing Shape in Drosophila melanogaster. Genetics. doi:10.1534/genetics.110.125922