A QUANTITATIVE TEST OF THE NEUTRAL THEORY USING POOLED ALLOZYME DATA

Neutral theory predicts a positive correlation between the amount of p olymorphism within species and evolutionary rate. Previous tests of th is prediction using both allozyme and DNA data have led to conflicting conclusions about the influence of selection and mutation drift. It i s argued here that quantitative conclusions about the adequacy of neut ral theory can be obtained by analyzing genetic data pooled from many sources. Using this approach, a large database containing information on allozyme variation in over 1500 species is used to examine the rela tionship between heterozygosity and genetic distance. The results prov ide support for the hypothesis that a major percentage of protein vari ation can be explained by variation in neutral mutation rate, and a mi nor percentage by strong selection.