Secular changes within Arctic and Sub-Arctic populations: a study of 632 human mandibles from the Aleutian Islands,...

A series of 632 human mandibles was used to test temporal variations in two Aleut populations and spatial variations in four homogeneous Greenlandic Eskimo populations. Sixteen metric variables and five non-metric observations were applied to generate univariate and multivariate statistics to determine variations caused by group homogeneity (Greenland), sexual dimorphism (Aleutian and Greenland), bilateral asymmetry (Aleutian and Greenland), temporal variation (Aleutians), and spatial variation (Greenland). The following results were obtained: (1) sexual dimorphism outweighed any other investigated variation, (2) no bilateral asymmetry was found in the metric variables, (3) temporal variation (Aleutian) was more significantly expressed in the male group than in the female group (patrilocal residence?), (4) spatial variation (Greenland) was more significantly expressed in the female group (matrilocal residence?), (5) the highest biological distance within the Greenlandic isolates was found between the Northeastern and Southeastern coastal areas, (6) variations in the mandible were related to metric changes rather than to changes in the morphological configuration, and (7) changes in non-metric frequencies (i.e., for mandibular tori as observed on the west coast of Greenland) were primarily induced by phenotypical variation (masticatory stress, changes in diet, ante-mortem loss of premolars and molars) caused by an inceptive increase of exogamic tendencies. The study concludes that as a single bone the human mandible yields a considerable quantity of information applicable to biological variations and reconstructions of biological and social histories, and that this information is conveniently available within the Arctic and Sub-Arctic populations.