Maximum likelihood estimation of human craniometric heritabilities

Abstract

This study presents univariate narrow-sense heritability estimates for 33 common craniometric dimensions, calculated using the maximum likelihood variance components method on a skeletal sample of 298 pedigreed individuals from Hallstatt, Austria. Quantitative genetic studies that use skeletal cranial measurements as a basis for inferring microevolutionary processes in human populations usually employ heritability estimates to represent the genetic variance of the population. The heritabilities used are often problematic: most come from studies of living humans, and/or they were calculated using statistical techniques or assumptions violated by human groups. Most bilateral breadth measures in the current study show low heritability estimates, while cranial length and height measures have heritability values ranging between 0.102-0.729. There appear to be differences between the heritabilities calculated from crania and those from anthropometric studies of living humans, suggesting that the use of the latter in quantitative genetic models of skeletal data may be inappropriate. The univariate skeletal heritability estimates seem to group into distinct regions of the cranium, based on their relative values. The most salient group of measurements is for the midfacial/orbital region, with a number of measures showing heritabilities less than 0.30. Several possible reasons behind this pattern are examined. Given the fact that heritabilities calculated on one population should not be applied to others, suggestions are made for the use of the data presented.

An alternative view of the peopling of South America: Lagoa Santa in craniometric perspective

“…According to Relethford and Harpending (1994), heritabilities for craniometric traits are fairly stable across populations, and an average estimation of h 2 = 0.55 that is based on Devor's study (1987) can be used. Most recently, Carson (2006) published narrow-sense heritability estimates for 33 craniometric dimensions using the maximum likelihood variance components method on a skeletal sample of pedigreed individuals from Hallastatt, Austria. In her study, she found low heritability estimates of most bilateral breadth measurements, while cranial length and height dimensions have heritability values ranging between 0.102 and 0.729 (Carson, 2006).…”

“…Most recently, Carson (2006) published narrow-sense heritability estimates for 33 craniometric dimensions using the maximum likelihood variance components method on a skeletal sample of pedigreed individuals from Hallastatt, Austria. In her study, she found low heritability estimates of most bilateral breadth measurements, while cranial length and height dimensions have heritability values ranging between 0.102 and 0.729 (Carson, 2006). The common practice of many researchers using the R-matrix method for human craniometric data is to average the reported narrow-sense heritabilities (h 2 = 0.55), which is a measure of the proportion of the total phenotypic variance that is due to additive genetic variance, or to assume that the phenotypic correlation is equivalent to the genotypic correlation (h 2 ≈ 1.0) (Carson, 2006).…”

Chinese immigrant population history in North America based on craniometric diversity

“…According to Relethford and Harpending (1994), heritabilities for craniometric traits are fairly stable across populations, and an average estimation of h 2 = 0.55 can be used (Devor, 1987). More recently, Carson (2006) published narrow-sense heritability estimated for 33 craniometric dimensions using a maximum likelihood variance components method on a skeletal sample of pedigreed individuals from Hallastatt, Austria. In that study, she found low heritability estimates of most bilateral breadth measurements, while cranial length and height dimensions have heritability values ranging between 0.102 and 0.729 (Carson, 2006).…”

“…More recently, Carson (2006) published narrow-sense heritability estimated for 33 craniometric dimensions using a maximum likelihood variance components method on a skeletal sample of pedigreed individuals from Hallastatt, Austria. In that study, she found low heritability estimates of most bilateral breadth measurements, while cranial length and height dimensions have heritability values ranging between 0.102 and 0.729 (Carson, 2006). Relethford and Blangero (1990) concluded that as long as the narrow-sense heritability for a traits was greater (Hanihara, 2008;Ishida et al, 2009) overall average heritabilities for craniometric traits of h 2 = 0.55 to compute the R-matrix.…”

Diversidade craniana humana e suas implicações evolutivas

“…Para o cálculo dos FST sobre dados craniométricos apresentados neste trabalho utilizou-se o programa Rmet 5.0 (Relethford, 2004b), adotando-se um grau de herdabilidade 40 (h 2 ) de 0,55, seguindo o proposto em outros estudos (Devor, 1987;Relethford, 1994;Roseman & Weaver, 2004;Carson, 2006).…”