The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Maximum heritability as an indicator of relative developmental stability among populations


1Maxwell Museum and Department of Anthropology, University of New Mexico, 2Craniofacial Biology Research Group, The University of Adelaide

Saturday 3:15-3:30, Parlors Add to calendar

Narrow sense heritability (h2) is the portion of phenotypic variation that is due to additive genetic variation, which is inversely related to environmental effects. Estimates of h2 are not generalizable, so assessing it in one population is not informative about any other population. Presumably, however, in populations with low resource competition, healthy nutrition, low disease rates, minimal pollution, and a high standard of living, individuals have fewer impediments to development, and therefore higher h2. If h2 estimates in such populations converge on a proportion, that proportion could potentially be an upper threshold, or “maximum heritability.” Estimated h2 in various populations could then be compared with this “maximum” as a relative indicator of developmental stability and potentially, secular change.

Carabelli’s trait is a frequently studied dental morphological characteristic for which h2 has been estimated in many different populations. Estimates of h2 for Carabelli’s trait range from 0.07 to 0.91. As a test of the concept of “maximum heritability,” this paper presents new h2 estimates for Carabelli’s trait from two populations that experience very high standards of living: Australians (n=300 twin pairs) and Americans (n=100 sibling and parent/offspring pairs) of European descent who were children during the last part of the 20th century. Across both dentitions among the Australians h2 is estimated as 0.74-0.81; work with the American sample is ongoing. Estimates for these two groups are compared with the literature to determine the extent to which h2 reflects what can be known about developmental health in various populations.

This work was supported by the National Health and Medical Research Council of Australia

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