Assistant Professor, Zoology Department

CGRB webpage

Research Interests:

My interests in evolutionary genetics and genomics are diverse.  The lab’s main research activities investigate the relative roles of mutation and natural selection in shaping nematode genome evolution using long-term sets of Caenorhabditis elegans mutation-accumulation (MA) lines.  The MA lines were propagated across hundreds of generations as single randomly selected hermaphrodites, resulting in an effective population size equal to one for each MA line.  This treatment severely reduced the efficiency of natural selection and ensured that mutations accumulated over time in an essentially neutral fashion.  By comparing molecular mutation spectra in the MA lines to patterns of genomic variation in C. elegans natural isolates, we have been able to gain new and unexpected insights into the relative roles of mutation and natural selection in shaping nematode genome evolution.  The MA lines also provide a system where mutation rates can be estimated in a uniquely direct and unbiased fashion – our work has shown that the “textbook” estimates of mutation rates are likely downwardly biased by at least a factor of ten.  The MA lines are also being used to examine the rate and spectrum of large genome rearrangements, and the roles played by mutation and selection in shaping transcriptome evolution using microarray technologies.  Multiple sets of DNA repair-deficient MA lines have provided insights into the relative roles of various repair pathways in maintaining C. elegans genome stability.  Future work will investigate the degree to which molecular mutation processes vary both within and between nematode species.  Experimental evolution studies with C. elegans are also planned that will explore the extent to which natural selection can shape mutation rates. 

On the penguin front, I am involved in paleogenomic studies that take advantage of Adélie penguin subfossil bones, ranging in age from 500 to 45,000 years before present.  The DNA from these bones is uniquely well-preserved due to the extraordinarily cold temperatures in the Antarctic.  I have successfully applied multiplex PCR approaches to amplifying complete mitochondrial genomes and numerous nuclear regions from these penguin subfossil DNA samples and am currently using the data to estimate molecular evolutionary rates in this species.  In the future, I aim to apply metagenomic approaches, using new high-throughput pyrosequencing technologies where up to 20 million bases can be sequenced in a day, to these unique ancient DNA resources.  This work is done in collaboration with David Lambert at the Allan Wilson Centre for Molecular Ecology and Evolution in New Zealand.

I also study the evolution of DNA repair genes and pathways throughout eukaryotic phylogeny using phylogenomic approaches.  Previous work focused on DNA glycosylases involved in base excision repair – all of the major DNA repair pathways will be targeted for similar studies in the future.

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