Scott George Richard, Stull Kyra E, Sbei Andrea N, McKinney Mason, Boling Scarlett R, Irish Joel D
Department of Anthropology, University of Nevada Reno, Reno, Nevada, USA.
Department of Anthropology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
Anat Rec (Hoboken). 2021 Aug;304(8):1776-1791. doi: 10.1002/ar.24566. Epub 2020 Nov 17.
Our goal is to describe the global distribution of the "rocker jaw" variant in human populations. Rocker jaw refers to mandibles that lack the antegonial notch, making them unstable on a flat surface. Data were collected by C.G. Turner II on 9,207 individuals from Asia, Europe, the Pacific, and the Americas, and by J.D. Irish on 3,526 individuals from North and South Africa. With a focus on Polynesia, where the trait is most common, frequencies are presented for subdivisions of Oceania, Australasia, Eurasia, the Americas, and Africa. While the rocker jaw is a Polynesian characteristic, the trait is found throughout the world. Within major geographic regions, there are interesting contrasts, for example, (a) the similarity of Jomon and Ainu and their difference from modern Japanese; (b) Aleuts and Northwest Coast Indians are similar and both are distinct from the Inuit and other Native Americans; and (c) North and Sub-Saharan Africans show a regional difference that parallels genetic and dental distinctions. Skeletons in South America that exhibit the rocker jaw have been interpreted as Polynesian voyagers who ventured to the west coast of South America. The rarity of rocker jaw in South American natives supports this view. The rocker jaw can be attributed to the unique basicranium morphology and large upper facial height of Polynesians, which highlights the integrated growth of a functional module (i.e., mastication) of the craniofacial complex. The unusually high frequency of the trait in Polynesians is a product of both function and founder effect/genetic drift.
我们的目标是描述人类群体中“摇椅颌”变体的全球分布情况。摇椅颌是指缺少下颌角切迹的下颌骨，这使得它们在平坦表面上不稳定。C.G.特纳二世收集了来自亚洲、欧洲、太平洋地区和美洲的9207人的数据，J.D.爱尔兰收集了来自北非和南非的3526人的数据。重点关注该特征最为常见的波利尼西亚，列出了大洋洲、澳大拉西亚、欧亚大陆、美洲和非洲各分区的频率。虽然摇椅颌是波利尼西亚人的特征，但在世界各地都能发现这一特征。在主要地理区域内，存在一些有趣的对比，例如：（a）绳文人和阿伊努人相似，与现代日本人不同；（b）阿留申人和西北海岸印第安人相似，且二者均与因纽特人和其他美洲原住民不同；（c）北非人和撒哈拉以南非洲人呈现出一种与基因和牙齿差异相似的区域差异。南美洲发现的具有摇椅颌的骨骼被解读为冒险前往南美洲西海岸的波利尼西亚航海者。南美洲原住民中摇椅颌的罕见性支持了这一观点。摇椅颌可归因于波利尼西亚人独特的颅底形态和较高的面部上半部分高度，这突出了颅面复合体功能模块（即咀嚼）的整体生长。该特征在波利尼西亚人中异常高的频率是功能以及奠基者效应/遗传漂变共同作用的结果。
