Division of Biological Anthropology, Department of Archaeology and Anthropology, University of Cambridge, Cambridge, CB2 3QG, UK.
Am J Phys Anthropol. 2014 Feb;153(2):167-77. doi: 10.1002/ajpa.22410. Epub 2013 Nov 13.
Sexual dimorphism in the human pelvis has been studied widely for forensic purposes, but it is still unclear to what extent it varies among human populations. There is evidence that microevolutionary processes, both neutral (i.e., population history) and selective (e.g., thermoregulatory adaptation and size-related obstetrical constraints) contribute to explain pelvic variation among populations, but the extent to which these factors affect pelvic sexual dimorphism is unknown. In this study, I analyze sexual dimorphism of the os coxae in 20 globally distributed human populations, using 3D morphometric data to separate the size and shape components of sexual differences. After evaluating population differences in the degree and pattern of sexual dimorphism, I test for the effect of population history, climate, and body size in shaping global diversity. The results show that size and shape dimorphism follow different patterns. Coxal size dimorphism is generally quite consistent through populations, with males bigger than females, but it appears to be reduced in small-bodied populations, possibly in relation to obstetrically-related selective pressures for a spacious birth canal. Beyond a general species-wide pattern of shape dimorphism, commonly used for forensic sex determination, other aspects of sexual differences in coxal shape vary among human populations, reflecting the effects of neutral demographic processes and climatic adaptation.
人类骨盆的性别二态性已广泛应用于法医学研究，但它在多大程度上存在于人类种群之间仍不清楚。有证据表明，微进化过程，包括中性（即种群历史）和选择性（例如，体温调节适应和与大小相关的产科限制），有助于解释种群之间的骨盆变异，但这些因素对骨盆性别二态性的影响程度尚不清楚。在这项研究中，我使用 3D 形态计量学数据来分离性差异的大小和形状成分，分析了 20 个人类种群中骨盆的性别二态性。在评估了性二态性的程度和模式在不同人群中的差异之后，我测试了人口历史、气候和体型对全球多样性形成的影响。结果表明，大小和形状的二态性遵循不同的模式。骨盆大小二态性在人群中通常非常一致，男性比女性大，但在体型较小的人群中似乎有所减少，这可能与宽敞的产道相关的产科选择性压力有关。除了常用于法医性别鉴定的常见物种范围的形状二态性模式外，骨盆形状的其他性别差异方面在不同的人群中也存在差异，反映了中性人口过程和气候适应的影响。
