Chapter 5 is devoted to the evaluation of population structure, admixture and gene flow over time. Employing particularly his data from the Black Caribs of Honduras, the Tlaxcaltecans of Mexico, the St. Lawrence Island Eskimos, and selected Siberian groups, he argues for significant correlations between genetics and geography, genetics and latitude, and genetics and language. Chapter 6 reviews what he considers the significant components of morphological variation. This chapter gives a summary of anthropometric, dermatoglyphic, dentition, and skin color studies. As the subtitle suggests, this is a solid review of the evidence from anthropological genetics, especially for the First Nations populations of North America.
Morphological studies are explicitly less considered.
Despite the main title, Crawford is less concerned with the current debates on origins, but more interested in providing us with a comprehensive synopsis of the advances made in studying variations of human genetics of First Nations, and in this he has succeeded admirably. References Crawford, Michael F. 1992 Antropologia Biologica de los Indios Americanos . Salzano, Francisco, and Sidia M. Callegari-Jacques. A Case Study in Evolution .