Maximum-likelihood variance components analysis of heritabilities of cranial nonmetric traits.

Full 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.

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Author information

Author/s: Carson, E Ann (EA);

Affiliation: Department of Anthropology, University of New Mexico, MSC 01-1040, Albuquerque, NM 87131, USA.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Human biology; an international record of research (Hum Biol), published in United States. (Language: eng)

Reference: 2006-Aug; vol 78 (issue 4) : pp 383-402

Dates: Created 2007/02/06; Completed 2007/03/15; Revised 2008/11/21;

PMID: 17278617, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Humans
Likelihood Functions
Male
Pedigree
Phenotype
Skull - anatomy & histology

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