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Genetic variability of crown structure in the molar

磨牙牙冠结构的遗传变异

基本信息

批准号：
17570196
负责人：
KONDO Shintaro
金额：
$ 2.18万
依托单位：
Aichi Gakuin University (2006-2007)Showa University (2005)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17570196/
关键词：
twin molar genetic variability cusp area genetic factor environmental factor sexual dimorphism tooth size 遺伝要因型歯冠細部構造異性二卵性双生児咬頭径歯冠ユニット

项目摘要

We compared the first molar sizes between opposite-sexed (OS) and same-sexed (SS) twins to analyze the environmental contributions to tooth size variation. In the maxilla, the mean values of the females were tended to be large in OS than in SS, but the mean values of males were larger in SS than in OS. In the mandible, the sexual differences in the tooth size showed the same pattern in both SS and OS twins. Dempsey, et al. (1999) reported that OS females had larger teeth than SS twins. They supposed that diffusion of sex hormones from male to female co-twins in utero might account for the increased tooth size in OS females. Their hypothesis was accord with the maxillary molars of our results, but our results of the mandibular molars were not accord. Our results indicated that the genetic effect was more affected in the mandibular molars than the maxilla.The cusp areas were measured on standardized photographs of the occlusal surface. Structural equation modeling was performed. There was no evidence of heterogeneity in variances of the cusp area between sexes. Genetic modeling indicated that a model incorporating additive genetic and unique environmental variation (AE model) was adequate for most of the cusp areas and crown areas. In some of these instances, a model incorporating common and unique environmental variance (CE model) provided an adequate fit. Estimates of heritability ranged from 47 to 85%. Overall crown area and crown unite areas showed higher heritability estimates than each cusp area. The paracone area showed the lowest heritability estimate in the measurements. The paracone is the first cusp in both ontogeny and phylogeny, and the most stable cusp of molars in primates. This result indicated that a stable cusp has been controlled by almost common genotypes throughout the human evolution processed.

我们比较了不同性别双生子（OS）和同性别双生子（SS）的第一磨牙大小，以分析环境因素对牙齿大小的影响。在上颌骨，女性的平均值往往是大OS比SS，但男性的平均值大于SS比OS。在下颌骨，在牙齿大小的性别差异表现出相同的模式在SS和OS双胞胎。Dempsey等人（1999年）报告称，OS女性的牙齿大于SS双胞胎。他们推测，性激素在子宫内从男性向女性的双胞胎扩散可能是OS女性牙齿尺寸增加的原因。他们的假设与我们的上颌磨牙的结果雅阁，而我们的下颌磨牙的结果不雅阁。我们的研究结果表明，遗传效应在下颌磨牙比在上颌骨更受影响。进行结构方程建模。没有证据表明两种性别之间的瓣尖面积方差存在异质性。遗传模型表明，一个模型，将加性遗传和独特的环境变化（AE模型）是足够的大部分的尖区和树冠面积。在其中一些情况下，一个模型，包括共同的和独特的环境方差（CE模型）提供了一个足够的拟合。遗传力的估计值范围为47%至85%。总冠面积和冠单位面积表现出较高的遗传力估计比每个尖区。旁锥体面积的遗传力估计值最低。副锥是灵长类磨牙发育过程中的第一个牙尖，也是最稳定的牙尖。这一结果表明，在整个人类进化过程中，一个稳定的尖端一直由几乎常见的基因型控制。