Stefan V H
Department of Anthropology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
Am J Phys Anthropol. 1999 Dec;110(4):407-19. doi: 10.1002/(SICI)1096-8644(199912)110:4<407::AID-AJPA3>3.0.CO;2-K.
Discrete cranial morphological traits of prehistoric/protohistoric Rapa Nui (Easter Island) inhabitants have been examined and have illustrated distinct regional or tribal differences; however, craniometric traits have not been as extensively evaluated to determine if similar regional population differences exist. This study examines the range of variability of Rapa Nui craniometrics and utilizes population genetic techniques to evaluate the level of homogeneity/heterogeneity within the island populations. The data consist of 50 cranio-facial measurements of Rapanui (Easter Islanders) skeletal material from the Late Prehistoric (1680-1722) and Protohistoric (1722-1868) periods. The sample was divided into five tribal regions: North, Northeast, South, Southwest, and West. General linear models (GLM) statistical analyses revealed one variable significant for males and 10 for females across tribal regions, totaling 11 regionally significant variables. Discriminant function analyses utilizing crossvalidation provided classification error rates of 55.8% males and 59.0% for females when utilizing those eleven significant variables. Minimum F(ST) values for males (0.06378) and females (0.09409) were calculated from unbiased Mahalanobis D(2) values. These values indicate that males have greater between-group homogeneity than females. The determinant ratio for the Northeast tribal region was the only significant ratio, yet all but one of the regional determinant ratios displayed a pattern of greater male than female mobility. These results indicate that significant craniometric differences between the tribal regions did not exist in prehistoric/protohistoric Rapa Nui populations, supporting the findings of previous research which has documented the homogeneity of the craniometrics of those tribal populations. The calculated minimum F(ST) values indicate the existence of different levels of heterogeneity between the male and female Rapa Nui regional populations resulting from differential levels of migration and gene flow. This variation reflects the establishment in prehistoric times of extensive tribal marriage tumus, and the existence of lineage endogamy/restricted exogamy, not the widespread practice of strict tribal endogamy.
对史前/原史时期拉帕努伊（复活节岛）居民的离散颅骨形态特征进行了研究，结果表明存在明显的区域或部落差异；然而，颅骨测量特征尚未得到广泛评估，以确定是否存在类似的区域人口差异。本研究考察了拉帕努伊颅骨测量的变异范围，并利用群体遗传学技术评估岛内各群体的同质/异质水平。数据包括来自史前晚期（1680 - 1722年）和原史时期（1722 - 1868年）的拉帕努伊（复活节岛人）骨骼材料的50项颅面测量数据。样本分为五个部落区域：北部、东北部、南部、西南部和西部。通用线性模型（GLM）统计分析显示，部落区域间男性有1个显著变量，女性有10个显著变量，共计11个区域显著变量。利用交叉验证的判别函数分析显示，使用这11个显著变量时，男性的分类错误率为55.8%，女性为59.0%。根据无偏马氏距离D(2)值计算出男性（0.06378）和女性（0.09409）的最小F(ST)值。这些值表明男性群体间的同质性高于女性。东北部部落区域的决定系数是唯一显著的系数，但除一个区域外，所有区域决定系数都显示出男性流动性高于女性的模式。这些结果表明，史前/原史时期的拉帕努伊人群部落区域间不存在显著的颅骨测量差异，这支持了先前研究的结果，即已记录到这些部落人群颅骨测量的同质性。计算出的最小F(ST)值表明，由于迁移和基因流动水平的差异，拉帕努伊男性和女性区域人群之间存在不同程度的异质性。这种差异反映了史前时期广泛存在的部落通婚习俗“图穆斯”，以及世系内婚制/有限外婚制的存在，而非严格部落内婚制的普遍实行。
