Department of Anthropology, University of Arkansas, Fayetteville, Arkansas.
Center for Bioarchaeological Research, School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona.
Am J Phys Anthropol. 2020 Jul;172(3):447-461. doi: 10.1002/ajpa.24019. Epub 2020 Feb 19.
This study generates a series of narrow-sense heritability estimates for crown morphology of the deciduous and permanent dentition with two overarching aims. The first is to test the hypothesis that deciduous teeth provide a more faithful reflection of genetic information than their permanent successors. The second is to use quantitative genetic methods to evaluate assumptions underlying common data collection and analysis practices in biodistance research.
Dental morphology data were collected from longitudinal dental casts representing Australian twins and families using Arizona State Dental Anthropology System standards. Polygenic models and estimates of narrow-sense heritability were generated using SOLAR v.8.1.1. Each model considered age, sex, and age/sex interaction as covariates.
Heritability estimates significantly differed from zero for the majority of morphological crown characters. Most estimates fell within the 0.4-0.8 range typically observed for crown morphology. Mean heritability was stable across the dental complex, but for paired homologues, permanent traits often yielded higher estimates than their deciduous counterparts. Results indicate directional asymmetry in environmental influence for crown morphology and inform biodistance "best practices" related to data collection and treatment.
Overall, results for this sample support the use of crown morphology as a proxy for genetic variation in evolutionary research. This includes the deciduous dentition, which justifies the expansion of efforts to incorporate subadults into reconstructions of past microevolutionary processes. Results do not indicate that deciduous phenotypes more closely approximate underlying genotype, at least for deciduous/permanent homologues.
本研究旨在通过两个总体目标，生成一系列关于乳牙和恒牙牙冠形态的狭义遗传力估计值。第一个目标是检验乳牙比其永久性后继者更能真实反映遗传信息的假设。第二个目标是使用数量遗传学方法来评估生物距离研究中常见数据收集和分析实践的假设。
使用亚利桑那州牙科人类学系统标准，从代表澳大利亚双胞胎和家庭的纵向牙模上收集牙齿形态数据。使用 SOLAR v.8.1.1 生成多基因模型和狭义遗传力估计值。每个模型都考虑了年龄、性别和年龄/性别交互作用作为协变量。
大多数形态牙冠特征的遗传力估计值显著不为零。大多数估计值落在通常观察到的牙冠形态 0.4-0.8 范围内。在整个牙齿复合体中，遗传力均值是稳定的，但对于成对的同源物，恒牙特征通常比其乳牙特征产生更高的估计值。结果表明牙冠形态的环境影响存在方向性不对称，并为与数据收集和处理相关的生物距离“最佳实践”提供信息。
总体而言，该样本的结果支持将牙冠形态作为进化研究中遗传变异的替代指标。这包括乳牙，这为将未成年人纳入过去微观进化过程重建的努力提供了依据。结果并不表明乳牙表型更接近潜在的基因型，至少对于乳牙/恒牙同源物而言。
