We have reviewed the available data on V(M), the amount of genetic variation in phenotypic traits produced each generation by mutation. We use these data to make several qualitative tests of the mutation-selection balance hypothesis for the maintenance of genetic variance (MSB). To compare V(M) values, we use three dimensionless quantities: mutational heritability, V(M)/V(E); the mutational coefficient of variation, CV(M); and the ratio of the standing genetic variance to V(M), V(G)/V(M). Since genetic coefficients of variation for life history traits are larger than those for morphological traits, we predict that under MSB, life history traits should also have larger CV(M). This is confirmed; life history traits have a median CV(M) value more than six times higher than that for morphological traits. V(G)/V(M) approximates the persistence time of mutations under MSB in an infinite population. In order for MSB to hold, V(G)/V(M) must be small, substantially less than 1000, and life history traits should have smaller values than morphological traits. V(G)/V(M) averages about 50 generations for life history traits and 100 generations for morphological traits. These observations are all consistent with the predictions of a mutation-selection balance model.
|Original language||English (US)|
|Number of pages||17|
|State||Published - 1996|
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