Research in our lab examines questions such as:
 

1) The evolution and population genomic consequences of mating system variation.

2) Conservation genomics of plant species.

3) The genomic basis of inbreeding depression.

4) The evolutionary consequences of somatic mutation in plants.

 

Current research:

 

Population genomics of range edge species. We are studying populations in the central and edge portions of the geographic range in two model plant species, Lupinus perennis and Impatiens capensis. Plant populations are increasingly threatened by habitat reduction and new selective pressures occurring under global climate change. The objective this work is to increase our knowledge of how plant populations are affected by genetic challenges that arise from habitat loss and global change, particularly those challenges associated with deleterious mutations or "genetic load." Given the accelerating reduction in genome sequencing costs, it is becoming increasingly common to predict potential fitness impacts of genetic load by analyzing genome sequence data with tools that quantify deleterious mutations using inferences derived from sequence conservation over evolutionary time and amino acid substitution, as well as from the application of statistical genetic methods to estimate the distribution of fitness effects of mutations. However, what has not been evaluated is the relationship between predictions obtained using genomic approaches and those from more direct assessments. We are examining and evaluating this relationship by applying genomic approaches to obtain predictions about genetic load and then comparing them with results from the measurement of fitness of progeny from controlled crosses.

 

We hope to bridge the gap between genomic predictions about the nature and fitness consequences of deleterious mutations and predictions based on direct fitness assessments. We are testing the value of genetic tools for making predictions about inbreeding load (the reduction in population fitness that arises from increased homozygosity of recessive deleterious mutations) as well as mutational load (the reduction in population fitness that arises from the increased fixation of deleterious mutations). We are also testing whether genomic tools can signal potential problems with adaptation to environmental stressors by examining the extent to which deleterious mutations are associated with genetic variation important for adaptive responses (and therefore possibly leading to selective interference), especially in populations at the northern edge of the geographic range, where populations may be important sources of propagules for founding new populations under global change scenarios.