Donald Waller

Donald Waller
Professor

Ph.D., Princeton University, 1978
Postdoctoral Research: Harvard University 

Address: 232B Birge Hall

Telephone: 608-263-2042

E-mail:

Department: Botany and Environmental Studies

Research Interests

Gene flow in relation to population genetic structure; Causes and consequences of inbreeding.

Research Fields

Evolutionary & Population Genetics
Plants

Research Description:

Small and/or inbred populations face many hazards including the accumulation of deleterious mutations (increasing the genetic load) and the increased expression of these mutations upon inbreeding (inbreeding depression). While inbred populations may eliminate some of their load via selection against deleterious recessive alleles, such purging is inefficient in small populations for that part of the load due to mildly deleterious mutations. We are measuring how quickly and completely purging of the load occurs in experimental populations of the fast-cycling self-incompatible annual plant, Brassica rapa. Evaluating how much purging occurs in small inbred populations helps us understand how selection modifies the evolution of plant reproductive characters like flower size and selfing rates. It also helps us understand what genetic threats exist for small and/or isolated populations such as those maintained under captivity. 

We also use isozyme and DNA markers to investigate gene flow and population differentiation in isolated populations of several plants, e.g., wild rice and several tropical tree species. These methods help to identify how genetic variation is distributed and maintained in natural plant populations. We also use markers to infer male and female reproductive success and thus selection on sexual characters in plants. 

Representative Publications:

Search PubMed for more publications by Donald Waller

Steven, J.C. and Waller, D.M. 2004. Reproductive alternatives to insect pollination in four species of Thalictrum (Ranunculaceae). Plant Species Biology 19:73-80. 

Keller, L. and Waller, D.M. 2002. Inbreeding effects in wild populations. Trends in Ecology and Evolution 17:230-241. 

Callahan, H.S. and Waller, D.M. 2000. Phenotypic integration and the plasticity of integration in an amphicarpic annual. International Journal of Plant Sciences 161:89-98. 

Byers, D. and Waller, D.M. 1999. Do plant populations purge their genetic load? Effects of population size and mating history on inbreeding depression. Ann. Rev. Ecol. Syst. 30:479-513. 

Byers, D., and D.M. Waller. 1999. Do plant populations purge their genetic load? Effects of population size and mating history on inbreeding depression. Ann. Rev. Ecol. and Syst. 30:479-513.