Meta-Analyses of the Association Between Multilocus Heterozygosity and Fitness

Meta‐analyses of published correlation coefficients between multilocus heterozygosity (MLH) and two fitness surrogates, growth rate and fluctuating asymmetry, suggested that the strength of these correlations are generally weak. A variety of plants and animals was included in the meta‐analyses. A statistically homogeneous group of MLH–growth rate correlation coefficients that included both plants and animals yielded a common correlation of rz = 0.133. A common correlation of rz = –0.170 was estimated for correlations between MLH and fluctuating asymmetry in three species of salmonid fishes. These results suggest that selection, including overdominance, has at most a weak effect at allozyme loci and cast some doubt on the widely held notion that heterozygosity and individual fitness are strongly correlated.