Doctoral Dissertation Research: Selection pressures on skull and pelvis proportions at birth

出生是所有人都必须经历的过程；然而，即使有现代医疗干预，它对母亲和婴儿都是危险的，可能是致命的。本博士论文项目研究了大量猴子和猿的头骨和骨盆形状的进化，以更好地了解不同灵长类谱系中分娩困难是如何以及何时出现的，并更好地确定人类面临的困难是我们物种独有的还是我们分类秩序共有的遗产。该项目促进女科学家的研究生培训，并可为医疗专业人员提供对人类分娩困难的更深入了解。这项研究的结果通过科普渠道向公众传播。由于产道和婴儿头骨之间的紧密配合，现代人类的分娩比黑猩猩和大猩猩等其他大型类人猿更危险，更容易导致婴儿或母亲死亡。因此，难产一直被认为是人类独有的进化特征，可能源于骨盆适应直立行走和异常大的大脑进化的结合。然而，据报道，体型较小的灵长类动物，如较小的类人猿和一些猴子，在分娩过程中会出现严重的并发症，包括母婴死亡。这就提出了一个问题：人类经历难产的原因是否与体型较小的灵长类动物相同，或者人类难产实际上是独一无二的。为了解决这个问题，该项目研究了灵长类动物头骨和骨盆的进化模式和自然选择，特别是在分娩的关键区域，使用3D扫描数据来比较头骨和骨盆形状差异的模式和大小，这些差异是基于猿和猴物种之间广泛的遗传关系。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Being born is a process all humans must experience; however, even with modern medical intervention, it is risky and potentially fatal for both mother and infant. This doctoral dissertation project examines the evolution of skull and pelvis shape in a wide range of monkeys and apes to better understand how and when birthing difficulties may have arisen in different primate lineages, and better determine whether the difficulties faced by humans are unique to our species or a legacy shared by our taxonomic order. This project fosters graduate student training of a female scientist and can provide a deeper understanding of the difficulty of human childbirth for medical professionals. Results of this research are communicated to the public through popular science outlets.Due to the tight fit between the birth canal and the infant skull, modern human childbirth is more dangerous and more likely to result in death for the infant or mother than in other large-bodied apes like chimpanzees and gorillas. As a result, difficult childbirth has historically been thought of as an evolved trait unique to humans, possibly stemming from the combination of pelvic adaptations to walking upright and the evolution of unusually large brains. However, smaller-bodied primates, such as the lesser apes and some monkeys, have been reported to experience serious complications, including maternal and infant death, during labor. This raises questions about whether humans experience difficult births for the same reason as smaller-bodied primates, or if difficult birth in humans is, in fact, unique. To address this question, this project investigates patterns of evolution and natural selection in the primate skull and pelvis, particularly in regions critical to childbirth, using 3D scan data to compare the patterns and magnitude of shape differences in the skull and pelvis to those expected based on genetic relationships among a wide sample of ape and monkey species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.