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

许多非人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。该项目模拟了几种灵长类动物犬齿和前磨牙大小的遗传，包括现代人类样本，以研究遗传结构对犬齿大小性别差异进化的影响。这些发现将用于理解人类谱系中犬科动物的减少和其他灵长类动物犬科动物的扩张机制，并有助于我们理解人类祖先的饮食、行为和牙齿之间的进化关系。与攻击性和饮食有关的选择性压力被假设为导致灵长类犬齿性别差异的原因，这些选择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领域培训一名女学生，制作一个将向其他研究人员公开的大型数据集，以及开展外延活动，如以提高公众对灵长类动物多样性和进化的理解为重点的公开讲座。牙齿特征为灵长类动物的遗传相关性提供了有价值的证据，牙齿的测量非常适合经典的定量遗传分析，这种分析使用系谱数据来估计性状的遗传能力。本项目评估了几个灵长类物种的犬齿和前磨牙尺寸的遗传遗传，具体目的是阐明这些牙齿形态性别差异的遗传机制。先前的研究人员已经指出，基因遗传中的性别差异以及雄性和雌性遗传物质的低重叠导致了性别差异的进化，但这些假设尚未在灵长类动物中得到验证。本项目主要研究三个基本问题：1)犬和前磨牙大小的性别差异是否与性状遗传的性别差异有关？2)同样的基因会影响上犬齿和下前臼齿的大小吗？3)在犬科动物中有性别差异的灵长类动物是否比没有性别差异的灵长类动物有更多的可进化的犬科动物？这些问题可以通过从已知血统的灵长类动物种群中收集的牙齿尺寸来回答。统计模型将用于估计每个种群中犬齿和前磨牙大小的遗传。对鞍背绢毛猴的初步数据收集和分析表明，雄性和雌性的性状遗传模式存在显著差异，但来自其他种群和物种的数据将证明这是灵长类动物普遍存在的，还是仅限于单个绢毛猴种群的特点。

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.