Doctoral Dissertation Research: Quantitative genetics of sexual dimorphism in primate teeth

许多非人类灵长类动物在犬齿和前磨牙的大小和形状上存在性别差异，但在人类谱系中，这些差异较小。这个项目模拟了几个灵长类动物的犬齿和前磨牙大小的遗传遗传，包括一个现代人类样本，以检查遗传结构对犬类大小性别差异进化的影响。这些发现将被用来理解犬类在人类谱系中减少和犬类在其他灵长类动物中扩张的机制，并有助于我们理解人类祖先饮食、行为和牙列之间的进化关系。与攻击性和饮食相关的选择性压力被认为是导致灵长类犬齿性别差异的原因，这些选择性压力的变化可能导致人类犬齿和前磨牙的减少。该项目将支持在STEM领域对一名女学生的培训，制作一个将向其他研究人员公开的大型数据集，以及诸如公共讲座等宣传活动，这些活动侧重于提高公众对灵长类多样性和进化的理解。牙齿特征提供了灵长类动物遗传相关的宝贵证据，牙齿测量非常适合经典的定量遗传分析，后者使用系谱数据来估计特征的遗传遗传力。该项目评估了几种灵长类动物犬齿和前磨牙大小的遗传遗传，旨在阐明这些牙齿形态性别差异的遗传机制。之前的研究人员曾表示，遗传上的性别差异以及雄性和雌性遗传物质的低重叠有助于性别差异的进化，但这些假说尚未在灵长类动物中得到验证。这个项目解决了三个基本的研究问题：1)犬类和前磨牙大小的性别差异是否与性状遗传中的性别差异有关？2)相同的基因是否影响上犬齿和下前磨牙的大小？3)犬类中存在性别差异的灵长类物种是否比没有性别差异的物种具有更多的犬类进化能力？这些问题可以通过从已知谱系的灵长类动物种群中收集的牙齿大小测量来回答。统计模型将被用来估计每个种群中犬类和前磨牙大小的遗传。对鞍背罗望子的初步数据收集和分析表明，雄性和雌性之间的特征遗传模式存在显著差异，但来自更多种群和物种的数据将证明这是灵长类的典型特征，还是仅限于单个罗望子种群的特有现象。

Many nonhuman primate species have sex differences in the size and shape of their canine and premolar teeth, but in the human lineage those differences are smaller. This project models the genetic inheritance of canine and premolar tooth size in several primate species, including a modern human sample, to examine the impact of genetic structures on the evolution of sex differences in canine size. The findings will be used to understand mechanisms of canine reduction in the human lineage and canine expansion in other primates, and contribute to our understanding of evolutionary relationships among diet, behavior, and dentition in our hominin ancestors. elective pressures related to aggression and diet are hypothesized to contribute to sex differences in primate canine teeth, and changes in these selective pressures may have led to human canine and premolar reduction. The project will support training of a female student in a STEM field, production of a large dataset that will be made public for other researchers, and outreach activities such as public lectures focused on improving public understanding of primate diversity and evolution.Dental characteristics provide valuable evidence of genetic relatedness in primates, and tooth measurements are well-suited to classical quantitative genetic analysis, which uses pedigree data to estimate the genetic heritability of traits. This project assesses the genetic inheritance of canine and premolar dimensions in several primate species with the specific aim of elucidating the genetic mechanisms underlying sex differences in the morphology of these teeth. Previous researchers have stated that sex differences in genetic inheritance and low overlap in male and female genetic material contribute to the evolution of sex differences, but these hypotheses have not been tested in primates. This project addresses three fundamental research questions: 1) Are sex differences in canine and premolar size associated with sex differences in trait inheritance? 2) Do the same genes impact the size of the upper canine and lower premolar? 3) Do primate species with sex differences in the canine have more evolvable canines than those with no sex differences? These questions can be answered using tooth size measurements collected from primate populations with known pedigrees. Statistical models will be used to estimate the inheritance of canine and premolar size in each population. Preliminary data collection and analyses of saddle-back tamarins indicate that there are significant differences between male and female patterns of trait inheritance, but data from additional populations and species will demonstrate whether this is typical of primates broadly or a peculiarity limited to a single tamarin population.