Archaeological research in the southern Channel Islands region of California suggests that migration resulted in a population replacement on the islands sometime during the past 6,000 years. This conclusion is drawn primarily from archaeologically recorded shifts in artifact assemblages and dietary habits on the island. Osteological analysis by Walker and Titus (1984) also supports the population replacement hypothesis, revealing higher frequencies of certain nonmetric cranial traits in early populations, as well as a change in cranial shape through time.
Three hypotheses of population replacement on the southern islands have been proposed/are found in the literature (Howard and Raab 1993, Martz 1994), but none are clearly supported by recent archaeological data. The purpose of this research is to test these hypotheses through the analysis of a large sample of human skeletal remains. Our research focuses on the temporal distribution of a suite of skeletal traits with high heritability as well as incorporating a considerable sample of cranial metric data.
Analyses of human skeletal remains from two of the southern Channel Islands (San Nicolas and San Clemente islands), as well as from northern Channel populations reveal a more complex interaction between groups than had previously been realized. Our data suggest that the demographic history of the southern Channel Islands is characterized by genetic input from several different island and mainland populations. These findings will result in a reevaluation of previously proposed hypotheses of island-island and island-mainland interaction.