UW Aquatic & Fishery Sciences Quantitative Seminar
UW School of Aquatic & Fishery Science
Does inbreeding reduce fitness in a natural salmon population? (Or, a geneticist's perspective on generalized mixed models and Bayesian statistics)
While it is widely recognized that evolutionary process may affect population productivity, detecting the casual factors affecting phenotypes is difficult in individuals that spend most of their time in natural environments. In these situations, genetic trends cannot be readily separated from environmental trends. However, if relationships between individuals are known, it is possible to study the inheritance of fitness-related traits and discriminate their genetic variability from environmental influences. The increasing availability of molecular pedigrees, coupled with the use of the “animal model”, has made it possible to achieve this goal. The animal model is a form of mixed effects model that takes into account the large number of relationships between individuals typically found in natural situations, as well as a variety of factors that might influence individual phenotypes. An example of where it is important to detect genetic effects on productivity is in managed populations, where inbreeding might lead to a change in fitness. These populations may appear demographically healthy, but management practices can result in inadvertent reductions in genetic variation underlying phenotypes. Here, the implementation of animal models in such situations will be explored using an extensive molecular pedigree of a steelhead hatchery population spanning four generations.