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1 August 2006 Maximum-Likelihood Variance Components Analysis of Heritabilities of Cranial Nonmetric Traits
E. Ann Carson
Author Affiliations +
Abstract

Nonmetric traits of the cranium are often used to support hypotheses of the history and divergence of human populations. These studies rely on the assumption that nonmetric traits are heritable, yet few skeletal series exist with associated pedigree information that allow for the calculation of additive genetic variance, or heritability. In addition, traits for which heritabilities have been published represent dichotomous present/absent forms instead of the range of expression that can be observed for many nonmetric characters. In the present study I use a maximum-likelihood variance components analysis to calculate univariate narrow-sense heritability estimates on the skeletal series from Hallstatt, Austria, for 9 sutural bones, 27 multilevel traits, and dichotomized present/absent forms for 19 of these multilevel characters. Most of the trait heritabilities do not differ significantly from a model of h2 = 0, and they have large standard errors. In a heuristic comparison of multilevel versus dichotomous trait forms, most of the nonmetric characters showed no differences in heritability between the two methods used for parsing the phenotypic variation, although where differences were noted, the presence-absence version had higher heritabilities. These results have implications not only for the use of particular nonmetric traits in population studies but also for the practice of character dichotomization in data collection.

E. Ann Carson "Maximum-Likelihood Variance Components Analysis of Heritabilities of Cranial Nonmetric Traits," Human Biology 78(4), 383-402, (1 August 2006). https://doi.org/10.1353/hub.2006.0054
Published: 1 August 2006
KEYWORDS
Austria
CRANIAL NONMETRIC TRAITS
heritability
maximum likelihood
pedigree analysis
variance components analysis
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