Genetic contributions to dental dimensions in brown‐mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta)

Abstract

Objectives: The use of dental metrics in phylogenetic reconstructions of fossil primates assumes variation in tooth size is highly heritable. Quantitative genetic studies in humans and baboons have estimated high heritabilities for dental traits, providing a preliminary view of the variability of dental trait heritability in nonhuman primate species. To expand upon this view, the heritabilities and evolvabilities of linear dental dimensions are estimated in brown-mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta). Materials and methods:Quantitative genetic analyses were performed on linear dental dimensions collected from 302 brown-mantled tamarins and 364 rhesus macaques. Heritabilities were estimated in SOLAR using pedigrees from each population, and evolvabilities were calculated manually.Results: Tamarin heritability estimates range from 0.19 to 0.99, and 25 of 26 tamarin estimates are significantly different from zero. Macaque heritability estimates range from 0.08 to 1.00, and 25 out of 28 estimates are significantly different from zero.Discussion: Dental dimensions are highly heritable in captive brown-mantled tamarins and freeranging rhesus macaques. The range of heritability estimates in these populations is broadly similar to those of baboons and humans. Evolvability tends to increase with heritability, although evolvability is high relative to heritability in some dimensions. Estimating evolvability helps to contextualize differences in heritability, and the observed relationship between evolvability and heritability in dental dimensions requires further investigation.

Genetic correlations in the dental dimensions ofSaguinus fuscicollis

“…Mesiodistal length measures of I 2 and I 1 were excluded from further analysis due to low intra‐observer measurement reliability of 0.17 and 0.32, respectively. Measurement reliability for the remaining traits ranged from 0.65 to 0.98 (see Hardin, ).…”

“…Estimated and actual crown areas have provided similar estimates of quantitative genetic parameters in previous studies (Hlusko et al, ). Intra‐observer measurement reliability was assessed with repeated measurements from 10 individuals (see Hardin, ).…”

“…Here, additive genetic variance ( σ 2 A ) was estimated in place of σ 2 G and hence the resulting heritability estimates reflected the narrow‐sense heritability ( h 2 = σ 2 A / σ 2 P ), rather than the broad‐sense heritability ( H 2 = σ 2 G / σ 2 P ). Maximum likelihood‐based variance decomposition was performed in SOLAR 8.1.1 (Almasy & Blangero, ; described in Hardin, ). Heritability estimates ( h 2 ) were significantly different from zero at p < .05 based on likelihood‐ratio tests.…”

“…Phenotypic similarities in dental morphology are therefore frequently used to approximate ancestor–descendant relationships, serving as proxies for genetic data that are unavailable in the fossil record. The use of dental traits in phylogenetic reconstruction is supported by the high heritabilities estimated from primate dental traits (Hardin, ; Hlusko, ; Hlusko & Mahaney, , ; Hlusko, Weiss, & Mahaney, ; Stojanowski, Paul, Seidel, Duncan, & Guatelli‐Steinberg, , ; Stojanowski, Paul, Seidel, Guatelli‐Steinberg, & Duncan, ). Quantitative genetic analyses can also bridge the gap between theories of mammalian dental patterning (Butler, ; Dahlberg, ; Evans et al, ; Kavanagh, Evans, & Jernvall, ; Osborn, ) and evaluations of phenotypic variation and covariation in primate taxa (Delezene, ; Gómez‐Robles, Smaers, Holloway, Polly, & Wood, ; Strait & Grine, ) to improve our understanding of the impact of genetic patterning on dental evolution (Hlusko, Schmitt, Monson, Brasil, & Mahaney, ).…”

Genetic Correlation, Pleiotropy, and Molar Morphology in a Longitudinal Sample of Australian Twins and Families

“…The field of quantitative genetics has also provided insight into these conditions, outlining the relative contribution of genes to tooth form and the coordination of genetic effects in determining dental phenotypes. In these efforts, pedigreed samples and relatedness coefficients approximate underlying additive genetic variation, which may (high heritability traits) or may not (low heritability traits) explain the structure of a corresponding dental data set—e.g., [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Quantitative genetic efforts also examine the potential for certain genetic effects to influence multiple dental characters ( pleiotropy ).…”