GENOMIC MUTATION-RATES FOR LIFETIME REPRODUCTIVE OUTPUT AND LIFE-SPANIN CAENORHABDITIS-ELEGANS

Theory concerning the evolution of sex and recombination and mutation load relies on information on rates and distributions of effects of de leterious mutations. Direct information on the genomic mutation rate i n Drosophila implies that an accumulation of mildly deleterious mutati ons reduces viability of populations by at least 1% per generation. We carried out an experiment to measure the deleterious mutation rate in Caenorhabditis elegans, in which independent sublines were maintained with one hermaphrodite parent per generation, conditions that minimiz e the opportunity for natural selection and lead to random fixation of deleterious mutations. After 60 generations of mutation accumulation, negligible changes in mean reproductive output and lifespan occurred, but the genetic variance increased at rates typical for life history traits in other species. The estimated deleterious mutation rate per h aploid genome for fitness, U, was 0.0026, a figure two orders of magni tude smaller than previously measured for viability in Drosophila.