Population Structure and Demographic History of Human Arctic Populations Using Quantitative Cranial Traits

The Arctic of North America provides an excellent laboratory for examining human population movement and differentiation. This research utilizes cranial morphological variation from 27 discrete Arctic populations spread across the North American Arctic to examine the role that culture and migration may have played in defining biological relationships and population structure among modern human Arctic populations. The unique pattern of cranial variation among Arctic populations, spread over a large and difficult environment, is the result of a complicated mixture of isolation, fragmentation, and migration. By examining this pattern using a number of statistics that quantify cranial morphological affinities and hence biological relationships, this work has provided a framework for explaining population structure differences and ancestor-descendent relationships. Most prominently, a pattern of ancestry and descent emerges from two primary sources, the Ipiutak at Point Hope and the Birnirk at Point Barrow. Overlapping in time, these two occupations along the north coast of Alaska appear to be fundamentally important in their contribution to the formation of variation patterns across the Arctic at the time of European contact. However, when the Ipiutak and Birnirk disappeared from the North Arctic coast, where did they go? This work lends additional support to the hypothesis that the Birnirk at Point Barrow are the formative ancestor to the Thule, from which modern Arctic populations are associated. Emerging out of the Birnirk, the Thule spread into the Central Arctic and Greenland, likely following aquatic food resources. There is support for biological continuity between the Birnirk and Greenland populations rather than the previously held supposition that the cultural continuum is based solely on a diffusion of culture. In contrast, the tight biological relationship between the Dorset-affiliated Sadlermiut and their neighboring Thule-associated groups suggests that cultural differences do not necessarily mean biological differences. The Ipiutak at Point Hope appear to have stronger affinities with historic west and northwest Arctic populations, including to a lesser extent the north Arctic Tigara population. Previous research suggests that as Point Hope became less hospitable, the Ipiutak went inland and south. Perhaps as the coastal climate improved, some Ipiutak returned to the coast, interacting to some extent with the Punuk and Birnirk associated populations, perhaps influencing the Thule technological complex and/or being influenced by it. The strong biological relationship of the Ipiutak to the west and northwest Arctic populations suggests that these populations were variably descendent from the Ipiutak