Jeff Dudycha

Assistant Professor of Biological Sciences & the School of the Environment
Ph.D. 1999, Michigan State University
Lab: EWS 610
803-777-3987
dudycha [at] biol.sc.edu

School of the Environment

Evolutionary Ecology, Genetics & Genomics in Freshwater Systems.

Research in our lab is rooted in evolutionary ecology, with the unifying goal of understanding adaptive & non-adaptive processes in nature by integrating information ranging from genes to communities. Our conceptual approach is to focus on traits, the features of organisms that set the boundaries of their distributions, mediate their interactions and drive their ultimate success or failure. Focusing on traits allows a mechanistic understanding of the feedback between ecological interactions and evolutionary change. We draw on a variety of disciplines to address fundamental questions about nature and biodiversity: To what extent do adaptive and non-adaptive evolution define the habitats in which a population can persist? How do traits interact, ecologically and evolutionarily, to produce organismal success or failure? How do ecological interactions influence the evolution of gene function, and vice-versa? What are the constraints on adaptation?

We use Daphnia, a common freshwater crustacean, to juxtapose ecological and genetic data in our explorations of adaptation and divergence as they proceed in the wild. Much of our work involves comparisons of populations along the pond-lake gradient, and the techniques we use span laboratory assays, field work, quantitative gentics, molecular evolution and genomics. Major projects the lab is pursuing include:

1. Genetic Architecture of Aging & its Adaptive Divergence. Expanding on previous work that showed ecological differences between Daphnia habitats (ponds vs. lakes) are probably driving evolutionary divergence of senescence between species, we seek to understand the genetic basis for this divergence and correlated life history traits. We are approaching this with a combination of quantitative genetics, molecular evolution, genomics and fieldwork.

2. Strange Patterns of Reproductive Isolation in Daphnia. Much of our work is directed at the ecological and evolutionary differentiation between populations of D. pulex (temporary ponds) and D. pulicaria (stratified lakes). However, these "species" are known to hybridize in the wild. Wild hybrids are invariably "obligately asexual", which as females reproduce only asexually, perhaps due to reproductive isolation between the taxa, perhaps due to inheritance of a sex limited meiosis-suppresor. Lab-bred hybrids, in contrast, are sexually competent, and we have developed a multi-stage model to explain the descrepancy between the wild and the tame. Our goals are to test the multi-stage model and conduct a widespread biogeographic analysis of reproductive isolation and hybrid performance in D. pulex and D. pulicaria.

3. Evolutionary Genetics & Genomics of Consumer-Resource Interactions. Much of our has drawn on the notion that trade-offs associated with aquiring, assimilating and allocating resources underpin life history evolution. We thus want to understand evolutionary divergence with respect to resource regime, and how adaptation to different resource environments re-casts the framework for life history evolution. Daphnia are ideal for this. They exist in replicate populations across a habitat gradient that produces major shifts in resource base and competitive pressures on Daphnia: ponds provide rich but dynamic resources and lakes provide poor but stable resources.

We are investigating the microevolution of resource exploitation by focusing on the power-efficiency tradeoff (power is the ability to exploit good resource conditions, efficiency is the ability to exploit poor resources) in a metapopulation that spans different resource conditions. We are also pursuing the genetic basis of such a trade-off, using a combination of physiological analysis, candidate genes and gene-expression microarrays.

Other interests in the lab include evolutionary responses to pollution, inbreeding depression, ecological & physiological regulation of sex development, pathogens in structured populations, heritability in the wild, molecular & ecological effects of spontaneous mutation accumulation, RNAi & transformation of live Daphnia.

Selected Publications:

McTaggart, S. J., J. L. Dudycha, A. Omilian & T. J. Crease. 2007. Rates of recombination in the ribosomal DNA of apomictically propagated Daphnia obtusa lines. Genetics 175: 311-320.

Omilian, A., M. E. A. Cristescu, J. L. Dudycha, & M. Lynch. 2006. Ameiotic recombination in asexual lineages of Daphnia. Proceedings of the National Academy of Sciences 103: 18638-18643.

Robinson, C.D., S. Lourido, S. P. Whelan, J. L. Dudycha, M. Lynch and S. Isern. 2006. Viral transgenesis of the freshwater microcrustacean Daphnia. Journal of Experimental Zoology 305A: 62-67.

Dudycha, J. L. and M. Lynch. 2005. Conserved ontogeny and allometric scaling of resource acquisition and allocation in the Daphniidae. Evolution 59: 565-576.

Dudycha, J. L. 2004. Mortality dynamics of Daphnia in contrasting habitats and their role in ecological divergence. Freshwater Biology, 49: 505-514.

Dudycha, J. L. and D. A. Roach. 2003. Pathogen frequency in an age-structured population of Plantago lanceolata. Oecologia 136: 141-147.

Dudycha, J. L. 2003. A multi-environment comparison of senescence between sister species of Daphnia. Oecologia 135: 555-563.

Dudycha, J. L. 2001. The senescence of Daphnia from risky and safe habitats. Ecology Letters 4(2): 102-105.

Dudycha, J. L. and A. J. Tessier. 1999. Natural genetic variation of life span, reproduction and juvenile growth in Daphnia. Evolution 53: 1744-1756.

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