Since the decline of salmonid populations in the Pacific Northwest, supplementation programs have become frequently implemented by hatcheries as a way to protect and conserve wild stock. However, hatchery-reared fish have lower fitness than wild fish which is likely due to adaptation to the hatchery environment, i.e., domestication selection. Fish...
Schistosomiasis is a neglected tropical disease caused by parasitic trematodes in the genus Schistosoma. 200 million people are infected with schistosomes. Schistosomiasis causes acute and chronic disease, and may lead to death in chronic infections. Schistosomes have a complex life cycle that requires passage through a snail intermediate host. Understanding...
Transgenerational immune priming occurs when an adult is exposed to a parasite or other pathogen and then transmits information to its offspring through protective phenotypes to cope with the same pathogen (Moret, 2006). There has been evidence for transgenerational immune priming in various invertebrates (Tidbury et al. 2011). Here we...
Releasing hatchery reared salmon and steelhead to supplement threatened and endangered populations is a widely used conservation tool. One issue with this strategy is hatchery fish have lower reproductive fitness than wild fish when spawning in the wild. One of the drivers of fitness loss in steelhead is adaptation to...
Schistosomiasis afflicts 200 million people and is responsible for 200,000 deaths per year. The infection is caused by a digenean trematode in the genus Schistosoma. The parasite must cycle through both a vertebrate (human) and invertebrate (snail) host to complete the life cycle. My dissertation focuses on the genetic mechanisms...
A primary goal of population genetics is to identify the role of
microevolutionary forces in producing observed patterns of molecular and phenotypic
variation. I conducted four studies in the northern leopard frog, Rana pipiens, to
determine just how mutation, migration, genetic drift, and selection influenced,
genetic structure of mitochondrial DNA...
Parasites are unique study organisms for evolutionary ecologists. Yet, molecular ecology studies on parasites have lagged far behind those on free-living organisms. The goal of the review in Chapter 2 was to illustrate areas of research that may be of particular interest in relation to the parasitic life style and...
A major goal of conservation biology is to elucidate the population genetic structure in threatened species and assess the relative importance of the evolutionary forces that shape that population genetic structure. I conducted three studies in the declining amphibian Rana cascadae to assess levels of population genetic differentiation and the...
This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary...
In this dissertation I study evolutionary patterns at genes encoding antimicrobial peptides (AMPs) in frogs. AMPs are short, amphipathic, cationic, secreted proteins that kill bacteria and other pathogens through a non-catalytic mechanism that involves
binding to and disrupting the microbial cell membrane. In many animal taxa, positive selection is much...
