A METAANALYSIS OF THE HERITABILITY OF DEVELOPMENTAL STABILITY

The existence of additive genetic variance in developmental stability has important implications for our understanding of morphological vari ation. The heritability of individual fluctuating asymmetry and other measures of developmental stability have frequently been estimated fro m parent-offspring regressions, sib analyses, or from selection experi ments. Here we review by meta-analysis published estimates of the heri tability of developmental stability, mainly the degree of individual f luctuating asymmetry in morphological characters. The overall mean eff ect size of heritabilities of individual fluctuating asymmetry was 0.1 9 from 34 studies of 17 species differing highly significantly from ze ro (P < 0.0001). The mean heritability for 14 species was 0.27. This i ndicates that there is a significant additive genetic component to dev elopmental stability. Effect size was larger for selection experiments than for studies based on parent-offspring regression or sib analyses , implying that genetic estimates were unbiased by maternal or common environment effects. Additive genetic coefficients of variation for in dividual fluctuating asymmetry were considerably higher than those for character size per se. Developmental stability may be significantly h eritable either because of strong directional selection, or fluctuatin g selection regimes which prevent populations from achieving a high de gree of developmental stability to current environmental and genetic c onditions.