Dynamics of genetic polymorphisms

The project will explore how well models and assumptions from theoretical population genetics fit to a real-life, natural population of Atlantic cod, by exploring the between- and within-generation dynamics of a select set of genetic polymorphisms. Differ ent classes of gene markers will be considered. The study material is a time-series (>20 years) of tissue samples and individual biological data from the well-described cod stock of the Trondheimsfjord, Norway. Annual samples from this s eries are already genotyped for 7 protein loci and one cDNA locus.In the project they will additionally be genotyped for six different VNTR loci, and scored for haplotype at one mtDNA cytochrome b sequence. Silent mutation haplotype frequencies at the latter will serve as an internal standard for pure genetic dr ift effects. The degree of temporal stability over ~ 20 years (4-5 cod generations) of allele frequencies at the VNTR loci will be analysed and compared between loci and with the standard. Estimates of Fst (or analogues) for the annual samples for each locus will be t ested for inter-locus homogeneity, for conformance with the neutral mtDNA marker, and for conformance with the expected values in a time-series from one population. Individua l biological information (age, sex, length, weight) will be used for exploring po tential within-generation effects at each locus. Full-sib offspring groups from controlled crossings with parents of known genotype will be used to test for Mendelian segreg ation and potential effect of single- and multilocus genotype and environment on g rowth and survival at each locus. nvironment on g Together, the various information sources in the study will allow a detailed insight into real-life dynamics of ge netic polymorphisms in a natural population, and in how well population markers in current use fulfill the theoretical assumptions, which for m a basis for their use as such. More light may also be shed on various mechanisms whereby the precious, and evol utionary so important, genetic variability is maintained in natural populations, as exemplified in a pilot study for the project.