Examining biological continuity across the late holocene occupation of the Aleutian Islands using cranial morphometrics and quantitative genetic permutation.

ABSTRACT

OBJECTIVES: The number of distinct human migrations into the Aleutian Islands during the Holocene has been a recurrent debate in the anthropological literature. Stemming from Hrdlicka's sorting of the prehistoric remains into two distinct populations based on archaeological context and cranial measurements, the human occupation of the Aleutian Islands has long been thought to be the consequence of two distinct human migrations, a Paleo-Aleut migration that provided the initial settlement of the islands, and a Neo-Aleut migration that replaced the original settlers around 1000 BP. This study examines the relationship of the Aleut cranial assemblages in the context of greater Alaskan population variability to assess the evidence for a substantial migration into the Aleutian Islands during the late Holocene. MATERIALS AND METHODS: A battery of 29 cranial measurements that quantify global cranial shape were analyzed using Euclidean morphometric methods and quantitative genetic permutation methods to examine the plausibility for two distinct Aleut occupations ("Paleo-Aleut" and "Neo-Aleut"), the latter of which is held to share closer phenetic affinities to mainland Alaskan populations than the former. The Aleut skeletal assemblages were arranged according to temporal association, geographic location, and cranial typology, and analyzed within a comparative framework of mainland Alaskan samples using principal coordinates, biological distance and random skewers permutation methods. RESULTS: Regardless of how the Aleut assemblages are divided, they show greater similarity to each other than to any of the mainland Alaskan assemblages. These findings are consistent across the methodological approaches. DISCUSSION: The results obtained in this study provide no support for a cranial morphology-based subdivision of the Aleuts into two distinct samples, Hence, there is no evidence for a substantial population migration of so-called Neo-Aleuts, nor for a population replacement event of an extant Paleo-Aleut population by a mainland-affiliated Neo-Aleuts population at or after 1000 BP.