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Evolutionary genetics of energetic performanceMontooth Lab |
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I began research in the Montooth Lab during the spring semester of my freshman year and have worked extensively on two projects since. My first project identified the causal genetic variants that underlie an incompatibility between segregating variation in the D. simulans mtDNA and variation in the D. melanogaster nuclear genome. The epistatic interaction of the SimW501 mtDNA and an OregonR nuclear background leads to several fitness costs at the organismal level such as delayed development, reduced fecundity, and a longer time to reproductive maturity. My Honors Thesis project, which was designed under the supervision of Luke Hoekstra, explores how the effect of the observed mitochondrial-nuclear epistasis in the (w501);ore genotype varies across different thermal environments. An abstract from my presentation of this project at the 2011 Midwest Drosophila Conference is shown below: An efficient and coordinated metabolism is essential for an organism's ability to develop and respond to environmental conditions. We are using Drosophila strains that pair divergent mitochondrial and nuclear genomes to explore how unique mitochondrial-nuclear genotypes affect metabolism and life-history. Previously, we identified particular combinations of D. melanogaster nuclear genomes and D. simulans mitochondrial genomes that significantly impact fitness. Here we demonstrate that the effects of these mitochondrial-nuclear incompatibilities are conditional on environmental temperature. The ability of larval metabolic rate to acclimate to the thermal environment is affected by mitochondrial-nuclear genotype. Development time and pupation height, both of which are traits potentially associated with energy availability, are also affected by interactions between mitochondrial-nuclear genotype and developmental temperature. The deleterious effect of mitochondrial-nuclear incompatibility increases with temperature, but there is also evidence that developmental plasticity provides homeostasis for metabolic rate. Together these results demonstrate thermodynamic constraint on performance via energy limitation, such that inefficiencies in metabolic processes are only revealed when temperature accelerates the rate of life. My research in the Montooth Lab has been an invaluable experience that has exposed me to key issues and ideas in evolution, genetics, and physiology. I am excited to build on this foundation while I pursue a Ph.D. in evolutionary genetics during graduate school.
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