Deleterious mutations and the genetic variance of male fitness components in Mimulus guttatus

Deleterious imitations are relevant to a broad range of questions in genetics and evolutionary biology. I present an application of the "biometric method" for estimating mutational parameters for male fitness characters of the yellow monkeyflower, Mimulus gattatus. The biometric method rests on two critical assumptions, The first is that experimental inbreeding changes genotype frequencies without changing allele frequencies; i.e., there is no genetic purging during the experiment. I satisfy this condition , employing a breeding design in which the parents are randomly extracted, fully homozygons inbred lines. The second is that all genetic variation is attributable to deleterious initiations maintained in mutation-selection balance. I explicitly test this hypothesis rising likelihood ratios. Of the three deleterions mutation models tested, the first two are rejected for all characters. The failure of these models is due to an excess of additive genetic variation relative to the expectation tinder mutation-selection balance. The third model is not rejected for either of two log-transformed male fitness traits. However, this model imposes only "weak conditions" and is not sufficiently detailed to provide estimates for mutational parameters. The implication is that, if biometric methods are going to yield useful parameter estimates, they will need to consider mutational models more complicated than those typically employed in experimental Studies.