Further fuel for the fiery debate over the origins of the initial inhabitants of the New World appears in this weeks issue of the Proceedings of the National Academy of Sciences. C. Loring Brace of the University of Michigans Museum of Anthropology and his colleagues analyzed data from prehistoric and recent human skulls from around the globe in an attempt to track early man's movements into the New World.

The researchers analyzed previously collected data on 1,988 human skulls from Europe, Asia and the Americas. Using 21 detailed measurements taken for each skull, the scientists compared both prehistoric and recent samples, and looked for similarities between various geographically separate groups.

They concluded that the earliest people inhabiting the Western Hemispheredating from 15,000 years agoresembled the population of modern and prehistoric Japan more than other, mainland Asian populations. Later arrivals to the New World, such as the Inuits and the Na-Dene-speaking people of the American Southwest, however, share more skull and facial traits with inland populations of Mongolian, Chinese and Southeast Asian descent, the researchers found.

The rise of agriculture, the scientists speculate, stimulated the major expansion of mainland East Asian populations into a variety of locales, including the New World. Because the areas were already occupied, the researchers write, the "consequence was a much greater rate of genetic exchange than had been true for any of the earlier movements."