ABSTRACT
The life on our planet displays an amazing range of diversity at all levels of biological organization: different kingdoms of life, several millions of species, and genetic diversity within species. Some of the genetic diversity within species is present simply as allelic differences (alternative forms of the same gene) carried by a single individual (heterozygosity), some occurs as genotypic differences among individuals living in the same local area, and some exists as allele frequency differences among different local populations. All of this genetic diversity is the product of the evolutionary process. Hence, to understand the significance of genetic diversity, it is necessary to place that diversity into its proper evolutionary context. Because evolution is a biological universal, the methods of analysis for interpreting genetic diversity are applicable to all species, including our own. Unfortunately, humans have tended to interpret their own intraspecific diversity in ways that are often inconsistent with how humans analyze and interpret genetic diversity in other species. As I show in this chapter, this is certainly the case concerning “racial” variation. From a scientific perspective, the interpretation of human genetic diversity in a unique manner is indefensible: A scientific understanding and interpretation of human genetic diversity must use the same criteria that have been applied to genetic diversity in nonhuman species. My primary goal in this chapter is to examine the significance of human genetic diversity, primarily racial diversity, using the same criteria and ana-lytical procedures applied to the remainder of life on this planet. This is not to say that humans are not a unique species—we certainly are—but it does acknowledge the fact that our genetic diversity is subject to the same basic types of evolutionary forces that shape diversity in all life.
