Statistical genetic comparison of two techniques for assessing molar crown size in pedigreed baboons
Statistical genetic comparison of two techniques for assessing molar crown size in pedigreed baboons
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DOI：
10.1002/ajpa.10022
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发表时间：
2002-02-01
影响因子：
2.8
通讯作者：
Mahaney, MC
中科院分区：
文献类型：
--
作者：
Hlusko, LJ;Weiss, KM;Mahaney, MC
牙齿人类学家和古人类学家通常使用估计的臼齿牙冠面积（近远中长度乘以颊舌宽度）来描述和比较个体、种群和物种。数字成像技术的进步使研究人员能够在二维平面上测量磨牙的实际牙冠面积。由于这种更精确的测量减少了误差，因此实际牙冠面积被认为是确定牙冠尺寸的机制的更好代表，我们通过估计来自个体样本（n = 332）的左下颌第二磨牙的这两个测量值的遗传度来验证这一假设。来自狒狒的圈养繁殖群。臼齿的实际和估计冠面积的遗传力估计值约为0.83。因此，这两个测量是翔实的人口描述符，没有显着差异的准确性，以反映添加剂的遗传贡献磨牙冠大小。这是幸运的，因为遗传研究和推断可以基于估计的面积而不是实际的树冠面积。近远中长和颊舌宽的遗传力估计值都很大，但较低：分别接近0.67和0.73。在这些分析中的最佳拟合模型表明，性别，身体大小，和亚种的亲和力差异影响磨牙的长度和宽度。我们解释这些结果表明，潜在的一些遗传基础这些协变量也是牙齿大小的基础。因此，设计用于描述臼齿牙冠大小的测量值可用于一般描述目的，但不符合系统发育分析中固有的独立性假设，例如分支系统学（Hennig [1966] Phylogenetic Systematics. Urbana：University of Illinois Press.因此，如果变量，如实际冠面积和估计冠面积是用于系统发育简约分析，我们建议研究人员占协变量，如性别和身体大小在他们的分析的影响。(C)2002年威利-利斯。
Dental anthropologists and paleoanthropologists commonly use an estimated molar crown area (mesiodistal length multiplied by buccolingual width) to describe and compare individuals, populations, and species. Advances in digital imaging now allow researchers to measure the actual crown area of a molar in an occlusal two-dimensional plane. Because error is reduced by this more accurate measurement, actual crown area is thought to be a better representation of the mechanisms that determine tooth crown size, meriting the additional time required to collect it. We tested this assumption by estimating the heritability of both these measurements for the second left mandibular molar from a sample of individuals (n = 332) from a captive breeding colony of baboons.Heritability estimates of both the actual and estimated crown areas of molars are approximately 0.83. Therefore, both measurements are informative as population descriptors, with no significant difference between the accuracy of either to reflect additive genetic contributions to molar crown size. This is fortunate, because genetic studies and inference can be based on estimated areas rather than actual crown area.The heritability estimates for mesiodistal length and buccolingual width are both substantial but lower: similar to0.67 and similar to0.73, respectively. The best fitting models in these analyses show that sex, body size, and subspecific affinity differentially affect molar length and width. We interpret these results to suggest that potentially some of the genetics underlying these covariates also underlie tooth size. As such, measurements designed to describe molar crown size are useful for general descriptive purposes, but do not conform to the assumption of independence inherent in phylogenetic analyses, such as cladistics (Hennig [1966] Phylogenetic Systematics. Urbana: University of Illinois Press). Therefore, if variables like actual crown area and estimated crown area are to be used in phylogenetic parsimony analyses, we suggest that researchers account for the effects of covariates such as sex and body size in their analyses. (C) 2002 Wiley-Liss.