Recent origin of low trabecular bone density in modern humans
Recent origin of low trabecular bone density in modern humans
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DOI：
10.1073/pnas.1411696112
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发表时间：
2015-01-13
影响因子：
11.1
通讯作者：
Richmond, Brian G.
中科院分区：
文献类型：
--
作者：
Chirchir, Habiba;Kivell, Tracy L.;Richmond, Brian G.
与我们现存的近亲（黑猩猩）和早期古人类化石相比，人类是独一无二的，因为我们拥有更大的体型和下肢关节面，以及相对柔软的骨骼（也就是说，相对于我们的体型来说，骨骼质量更低）。一些分析已经观察到，至少在一些解剖区域，现代人类的骨小梁密度相对较低，但对于这种密度在整个人类骨骼和不同物种之间是如何变化的，以及目前的骨小梁模式是如何以及何时在人类进化过程中出现的，我们知之甚少。在这里，我们测试了以下假设：(1)与其他灵长类类群相比，近代现代人的上肢和下肢小梁密度较低；(2)小梁密度的减少首先发生在早期直立人，与现代人运动解剖学的转变相一致，或者最近与全新世人类的干骺端扁平化相一致。我们使用外围定量CT和显微断层扫描测量了现代人类和黑猩猩的肢体骨骺小梁骨（长骨关节末端），以及被认为是非洲南方古猿、鲁棒猿人/早期斯瓦特克兰人、尼安德特人和早期智人的古人类化石。结果表明，只有最近的现代人类在整个肢体关节中有低的小梁密度。已灭绝的古人类，包括全新世以前的智人，保留了非人灵长类动物的高水平。因此，现代人类骨骼的低骨小梁密度是在人类进化史的晚期进化而来的，这可能是由于定居行为的增加以及对技术和文化创新的依赖。
Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/ early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations.