Pelvic Shape and Differential Mortality: Obstetric Variation Among Indigenous North American Populations

这项研究考察了骨盆尺寸和自然选择的关系，因为它与女性的死亡年龄和过去北美土著群体的气候有关。研究人员预测，女性盆腔入口狭窄，这是一种衡量产科效率(无并发症分娩的能力)的指标，将导致年轻和老年个体更高的死亡率。此外，以前的研究已经将骨盆形状，特别是臀部宽度与体温调节联系起来。身体较宽的个体相对于身体质量有较小的表面积，因此在保持身体热量方面更有效率。北美原住民被证明拥有比他们生活的纬度所期望的更宽的身体。因此，它们的体型可能与祖先共同居住在较冷的气候中有关，这一特征后来被后代种群所共有。尽管气候可能在较温暖的气候中选择了较窄的身体，但产科效率可能已经减弱了这种压力。尽管个人死亡的年龄与多种因素有关，但年轻人的平均死亡率与盆腔出口狭窄的尺寸之间的相关性将支持骨盆形状和产科并发症作为女性的选择因素。此外，如果骨盆出口的形状与整个臀部宽度一致，这将表明骨盆形状确实是至少两种选择压力之间的平衡：气候和产科。从更广泛的角度来看，这个项目有助于理解迁徙人类遇到的生物变化以及影响这些变化的因素。它有助于进一步了解人类之间的体型差异。这项研究将把博士前学生纳入主要骨骼存储库的数据收集，并鼓励学生进行进一步研究。此外，与莱比锡马克斯·普朗克研究所的博士后研究员合作开发的捕获和比较形状数据的新方法将被创造出来，并与其他研究人员分享。

This research examines the association of pelvic dimensions and natural selection as it relates to both age-at-death in females and climate among past indigenous North American groups. The investigators predict that narrow pelvic inlets in females, a measure of obstetric efficiency (the ability to give birth without complications) will have caused higher death rates in young aged individuals. In addition, previous studies have linked pelvic shape, especially hip breadth, to body heat regulation. Individuals with wider bodies have less surface area relative to body mass, and therefore are more efficient at retaining body heat. Indigenous North Americans have been shown to possess wider bodies than would be expected for the latitudes in which they lived. Thus, their body shape may be related to common ancestral occupation of colder climates, a trait then shared by descendent populations. Although climate may have selected for narrower bodies in warmer climates, obstetric efficiency may have attenuated this pressure. Although multiple factors are related to the age at which individuals died, a correlation between young aged mean mortality and narrow dimensions in the pelvic outlet would support pelvic shape and obstetrical complications as a selective factor among females. Furthermore, if the shape of the pelvic outlet covaries with overall hip breadth, this would indicate that pelvic shape is indeed a balance between at least two selective pressures: climate and obstetrics.Broadly, this project contributes to the understanding of biological changes encountered by migrating humans and factors influencing those changes. It contributes further to an understanding of body shape variation among humans. The study will incorporate pre-doctoral students in data collection at major skeletal repositories and encourages students toward the development of further studies. Furthermore, new methods for capturing and comparing shape data, developed in collaboration with a postdoctoral researcher at the Max Planck Institute in Leipzig, will be created and shared with other researchers.