9417753 KONDRASHOV Recent experimental data suggest that many organisms experience high total rates of slightly deleterious mutations (1 or more per generation). This means that selection against such mutations is intense and can influence various aspects of populations. A general representation of mutation-selection balance will be developed, which allows for arbitrary patterns of selection, and for the evolution of genes that modify the genetic system. This representation will be based on consideration of the number of mutant alleles in the genome, and on application of the methods of quantitative genetics of such traits. This representation will be applied to investigate three problems: 1) the evolution of the length of the haploid and diploid phases; 2) the coevolution of mutability and facultative asexuality or selfing; and 3) the coevolution of recombination and inbreeding. Both mathematical and computer models will be used. The results will contribute to the understanding of the general features of selection against slightly deleterious mutations, and of the evolution of life cycles, reproduction, and mutability.
