William J. Etges
J. William Fulbright College of Arts & Sciences
Our group uses ecological, physiological, genetic, and systematic approaches to adaptation and speciation. A majority of work involves study of the relationships between desert Drosophila and their host plants due to the wealth of previous knowledge of this fascinating system.
- We are assessing the ecological genomics of D. mojavensis populations characterized by different life histories, use of different host plants, courtship songs, and epicuticular hydrocarbon profiles. Results of gene expression studies has allowed us to identify transcriptional differences associated with different host cacti, across different life stages and ages, responses to temperature and desiccation differences, and allow comparison of gene expression profiles in wild vs. laboratory reared flies. We are particularly interested in understanding genomic responses to heat and desiccation stress as a model for understanding the consequences of global warming in this well studied desert species.
- Genetic and ecological determination of sexual isolation among geographically isolated populations of Drosophila mojavensis has been analyzed in QTL studies of male courtship songs, epicuticular hydrocarbon variation, mating success, and egg to adult development time. Rearing substrate differences had significant effects on QTL detection for all traits and caused numerous GxE interactions. A single QTL was detected that influenced mating success: this QTL is 12.3 Kb from desat-2 that is involved in cuticular hydrocarbon production. We are optimistic that these and other candidate gene regions can be further exploited in future association studies.
- Together with Konrad Lohse (Univ. Edinburgh), Mike Ritchie, and invaluable input from Alfredo Ruiz, genomes of D. arizonae, D. mojavensis, and D. navojoa have been sequenced and compared for divergence in collinear and inverted chromosomal regions. Due to the number of fixed and polymorphic gene arrangements in these species, it is possible to assess the role of inversions during species divergence. Konrad has revealed that despite the absence of recent hybridization between D. arizonae and D. mojavensis, post-divergence gene flow occurred up until ca 250 kya, about the same time mainland and Baja California populations of D. mojavensis became isolated. Assessment of population level genomic divergence among populations of D. mojavensis is underway.
Evolutionary biology, ecological genomics, population and quantitative genetics
M.S. University of Georgia, 1979
Ph.D., University of Rochester, 1984
Etges, W. J. C. C. de Oliveira, Rajpurohit, S., and A. G. Gibbs. 2016. Effects of temperature on transcriptome and cuticular hydrocarbon expression in ecologically differentiated populations of desert Drosophila. Ecology and Evolution, in press.
Etges, W. J., C. C. de Oliveira, S. Rajpurohit, and A. G. Gibbs. 2016. Preadult life history variation determines adult transcriptome expression. Molecular Ecology 23:741-763.
Lohse, K., M. Clark, M. G. Ritchie, and W. J. Etges. 2015. Genome-wide tests for introgression between cactophilic Drosophila implicate a role of inversions during speciation. Evolution 69:1178-1190. doi:10.1111/evo.12650, Supplementary information.
Etges, W. J., M. V. Trotter, C. C. de Oliveira, S. Rajpurohit, A. G. Gibbs, and S. Tuljapurkar. 2015. Deciphering life history transcriptomes in different environments. Molecular Ecology 24:151-179. DOI: 10.1111/mec.13017
Delprat, A., W. J. Etges, and A. Ruiz. 2014. Reanalysis of polytene chromosomes in Drosophila mojavensis populations from Santa Catalina Island, California, USA. Drosophila Information Service 97:53-57.
Etges, W. J. 2014. No boundaries: genomes, organisms, and environmental interactions responsible for divergence and reproductive isolation. Journal of Heredity 105:756-770, (Special issue on speciation) 10.1093/jhered/esu039. (journal cover)
1987-present: Assist., Assoc., Full Professor, Department of Biological Sciences, Program in Ecology and Evolutionary Biology, and Program in Cell and Molecular Biology, University of Arkansas.
2007-2008: Cambridge Research Fellow, Fulbright College, Wolfson College and Department of Genetics, University of Cambridge.
1985-1987: NSF Postdoctoral Fellow, Department of Ecology and Evolutionary Biology, University of Arizona, mentor: William B. Heed.
1984-1985: Visiting Assistant Professor, Department of Ecology and Evolutionary Biology, University of Arizona.
1980-1983: NIH Predoctoral Fellow, University of Rochester.
1977-1979: Savannah River Ecology Laboratory Summer Research Fellow.