Abstract
Modern humans evolved in Africa and spread around the rest of the world only within the past 80 to 100 thousand years. During that process and subsequently allele frequency differences among the populations arose and those differences have great biomedical implications. The overall genetic pattern reflects the original expansion pathways out of Africa, but individual loci can vary greatly from that pattern. In contrast to the belief in distinct biological races, we see nearly continuous genetic variation across the globe among indigenous populations. While variation occurs, it is impossible to draw a line separating “races”. Examples of population variation in alleles relevant to cancer risk and therapeutic outcomes illustrate the global differences that do exist. Populations arising more recently with ancestry from geographically separated parts of the world have a mosaic pattern of ancestral DNA along their chromosomes such that an overall level of admixture is a poor predictor of the ancestral origins of alleles at any specified locus. These considerations become important in more personalized medicine.
Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):ED04-03.
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