Context of maternal lineages in the greater Southwest

A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase chain reaction. The enzyme, isolated from Thermus aquaticus, greatly simplifies the procedure and, by enabling the amplification reaction to be performed at higher temperatures, significantly improves the specificity, yield, sensitivity, and length of products that can be amplified. Single-copy genomic sequences were amplified by a factor of more than 10 million with very high specificity, and DNA segments up to 2000 base pairs were readily amplified. In addition, the method was used to amplify and detect a target DNA molecule present only once in a sample of 10(5) cells.

The rapid spread of Numic peoples into the Great Basin about 500-700 years ago is a major anomaly in the prehistory of that region because, according to current interpretations, it occurred in the absence of major adaptive change. A review of existing evidence suggests that this view is incorrect; we propose an alternative notion of important contrasts between Prenumic and Numic adaptation in terms of the relative reliance on large game and small seeds. These contrasts explain why the Numic speakers were consistently able to expand at the expense of Prenumic groups.