9615567 KRAUSE The degree to which genetic variation for metabolic enzymes can potentially translate into biochemical, physiological and fitness differences among individuals is largely unknown. Previous studies suggest that protein variation for an enzyme involved in energy metabolism from the bay scallop, Argopecten irradians, directly affects biochemical and production-related traits. Scallop size, reproductive output, and certain biochemical traits are associated with genetic variation for the enzyme glucose phosphate isomerase (Gpi). The proposed research will build on previous work and examine DNA sequence variation for the Gpi gene. DNA from individuals with different Gpi protein variants will be sequenced following isolation and amplification by the polymerase chain reaction. A variety of statistical tests will be applied to the nucleotide sequence data in order to test hypotheses regarding the relative strength of random and selective forces maintaining genetic variation at Gpi. Also, the relationships among nucleotide variation and previously characterized protein and size differences among scallops will be explored. The results from this study will contribute to the general body of knowledge describing the relative roles of random and selective forces in evolution. More importantly, these data will begin to address the functional relevance of nucleotide variation and the hypothesis that genetic differences for this glycolytic enzyme translate into fitness differences among individuals in a population.
