Center for Bioarchaeological Research, School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona.
Department of Sociology and Anthropology, East Tennessee State University, Johnson City, Tennessee.
Am J Phys Anthropol. 2019 Mar;168(3):606-631. doi: 10.1002/ajpa.23778.
This article presents estimates of narrow-sense heritability and bivariate genetic correlation for 14 tooth crown morphological variants scored on permanent premolars, first molars, and second molars. The objective is to inform data collection and analytical practices in dental biodistance and to provide insights on the development of molar crowns as integrated structures.
African American dental casts from the Menegaz-Bock collection were recorded for the Arizona State University Dental Anthropology System. Estimates of narrow-sense heritability and genetic correlation were generated using SOLAR v.8.1.1, which included assessment of age, sex, and birth year as covariates. Both continuous scale and dichotomized estimates are provided.
Heritability estimates were nonsignificant for the majority of variables; however, for variables yielding significant estimates, values were moderate to high in magnitude and comparable to previous studies. Comparing left and right-side heritability estimates suggests directional asymmetry in the expression of environmental variance, something not seen in anterior tooth traits. Genetic correlations were moderate among antimeres and metameres and low for different traits scored on the same tooth crown. Although several negative correlations were noted, few reached statistical significance. Results affirm some of the current data cleaning and analytical practices in dental biodistance, but others are called into question. These include the pooling of males and females and combining left and right-side data into a single dataset.
In comparison to anterior tooth crown traits, postcanine heritabilities were more often non-significant; however, those traits with significant heritability also tended to produce higher estimates. Genetic correlations were unremarkable, in part, because they were underpowered. However, M1 results may provide insight into the complex relationship between genes, environment, and development in determining ultimate crown form.
本文报告了在恒前磨牙、第一磨牙和第二磨牙上得分的 14 种牙冠形态变异的狭义遗传率和双变量遗传相关的估计值。目的是为牙生物距离的数据分析和收集提供信息，并深入了解磨牙冠作为一个整体结构的发育情况。
从 Menegaz-Bock 收藏中记录了非裔美国人的牙模，用于亚利桑那州立大学牙科人类学系统。使用 SOLAR v.8.1.1 生成了狭义遗传率和遗传相关的估计值，其中包括年龄、性别和出生年份作为协变量进行评估。提供了连续尺度和二分估计值。
大多数变量的遗传率估计值没有意义；然而，对于产生显著估计值的变量，其数值在中等至高水平，与之前的研究相当。比较左右侧遗传率估计值表明，环境方差的表达存在方向性不对称，这在前牙特征中没有出现。对侧牙之间的遗传相关度较高，同一牙冠上得分的不同特征之间的遗传相关度较低。尽管注意到了几个负相关，但很少有达到统计学意义。结果肯定了牙生物距离研究中一些当前的数据清理和分析实践，但也有一些受到质疑。这包括将男性和女性混合在一起，以及将左右侧数据合并到一个数据集。
与前牙冠特征相比，后磨牙的遗传率更常无意义；然而，那些具有显著遗传率的特征也往往产生更高的估计值。遗传相关度不显著，部分原因是其功效不足。然而，M1 的结果可能为基因、环境和发育在确定最终冠形态方面的复杂关系提供了一些启示。
