Doctoral Dissertation Improvement: Coevolutionary Models and the Evolution of the Anthropoid Honing Complex

博士论文改进：共同进化模型和类人猿珩磨复合体的进化

• 批准号: 0852105
• 负责人: William Kimbel
• 金额: $ 0.18万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0852105&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; Coevolutionary; Models

Two features, bipedality and reduced canine size, distinguish humans and our fossil ancestors from other apes. In monkeys and apes the canines are typically relatively large and participate in a functional complex that sharpens the canines during occlusion; the reduced hominin canine is not sharpened. Characters within functional complexes are expected to coevolve as a result of natural selection and, among nonhuman anthropoid primates, two characters of this complex have been shown to be correlated among species, suggesting that characters of the complex do coevolve. A similar pattern is not observed in early hominins of the genus Australopithecus. Thus, the canine honing complex provides a rare opportunity to investigate the coevolution and dissolution of a functional complex. Character coevolution occurs as the result of different processes; for example, characters may coevolve because of genetic correlations, created by pleiotropy or genetic linkage, which exist among characters. Coevolution, observed among species, is in this case an extension of the genetic relationship that exists within species. Coevolution occurs in the absence of genetic correlations as well if characters respond independently to selection, which is termed selective covariation. This project will determine if characters of the honing complex coevolve and, if so, by which process. Genetic correlations in nonhuman primates would require a genetic decoupling of the complex during hominin evolution; however, the absence of genetic correlations would only require a change in the source or strength of selective pressures to break up the complex. By examining patterns of covariation, both within and among species, the process(es) that holds the complex together in extant nonhuman anthropoids will be elucidated as will be the process that decoupled the complex in hominins. This project will investigate the origin of canine reduction, one of the hallmark features of hominin evolution. To address this topic, the morphology of the primate dentition will be quantified using caliper- and photographic-based measurements. Measurements will be taken on a broad sample of primate dentitions to ensure that the sample is broad phylogenetically, in body size, and in social structure.

人类和我们的化石祖先区别于其他类人猿的两个特征是两足动物和较小的犬类。在猴子和类人猿中，犬齿通常相对较大，并参与在咬合过程中磨尖犬齿的功能复合体；减少的原始犬齿不会被磨尖。功能复合体中的特征被认为是自然选择的结果，在非人类类人灵长类动物中，这种复合体的两个特征被证明在物种之间是相关的，这表明该复合体的特征确实是共同进化的。在南方古猿属的早期原始人中没有观察到类似的模式。因此，犬科磨牙复合体提供了一个难得的机会来研究功能复合体的共同进化和溶解。字符共同进化是不同过程的结果；例如，字符之间可能因为存在多效性或遗传连锁而产生的遗传相关性而共同进化。在物种之间观察到的共同进化，在这种情况下是物种内存在的遗传关系的延伸。如果性状独立地对选择作出反应，则在没有遗传相关性的情况下也会发生协同进化，这被称为选择性协变。这个项目将确定研磨复合体的特征是否共同进化，如果是，通过哪个过程。在非人类灵长类动物中，遗传相关性需要在原始人进化过程中对复合体进行基因分离；然而，缺乏遗传关联性只需要改变选择压力的来源或强度来分解复合体。通过研究物种内部和物种间的协变模式，将阐明将现存的非人类类人猿中的复合体结合在一起的过程，以及将人类中的复合体分离的过程。这个项目将调查犬类减少的起源，这是人类进化的标志性特征之一。为了解决这个问题，将使用卡尺和基于摄影的测量来量化灵长类牙齿的形态。将对灵长类牙齿的广泛样本进行测量，以确保样本在系统发育、身体大小和社会结构方面是广泛的。