Published online by Cambridge University Press: 14 April 2009
Three tests of neutral theory were carried out using a large dataset of vertebrate allozyme studies. The first test considered the relationship between the mean and variance of single locus heterozygosity across a sample of enzymes and non-enzymatic proteins. The second test compared the distributions of heterozygosity between paired proteins in balanced datasets in which each protein is scored for the same sample of species. The third test compared the observed distribution of single locus heterozygosity with theoretical distributions predicted by neutral theory. The results show an excellent quantitative fit with the predictions of neutral theory, though some small deviations from neutrality were observed which are consistent with the action of natural selection.