Human Races: A Genetic and Evolutionary Perspective

Abstract

Race is generally used as a synonym for subspecies, which traditionally is a geographically circumscribed, genetically differentiated population. Sometimes traits show independent patterns of geographical variation such that some combination will distinguish most populations from all others. To avoid making "race" the equivalent of a local population, minimal thresholds of differentiation are imposed. Human "races" are below the thresholds used in other species, so valid traditional subspecies do not exist in humans. A "subspecies" can also be defined as a distinct evolutionary lineage within a species. Genetic surveys and the analyses of DNA haplotype trees show that human "races" are not distinct lineages, and that this is not due to recent admixture; human "races" are not and never were "pure." Instead, human evolution has been and is characterized by many locally differentiated populations coexisting at any given time, but with sufficient genetic contact to make all of humanity a single lineage sharing a common evolutionary fate.

Does life-course socioeconomic position influence racial inequalities in the occurrence of uterine leiomyoma? Evidence from the Pro-Saude Study

“…The investigation of such biological mechanisms, possibly resulting from phenotypic features, would not mean an endorsement of genetic inheritance as the basis for racial classifications. The wide variability of humans' external physical characteristics, commonly used to describe racial groups, seems to reflect changes and adjustments, over the mil-lennia, to variations of climate and other environmental factors, as well as historical and social conditions 22,59,60,61 .…”

Prevalência de oclusopatia na dentição decídua e permanente de crianças na cidade de São Paulo, Brasil, 1996

“…Estudos objetivando compreender as fontes da variação humana revelaram que aproximadamente 85% de toda a variação na freqüência genética ocorrem dentro dos mesmos grupos populacionais, e somente 15% são observados entre as populações com traços físicos reconhecidamente diferentes. Assim, do ponto de vista da genética, considerar os traços físicos mais marcantes como um conceito biológico que traduz populações geneticamente homogêneas é insustentá-vel e não encerra mais legitimidade no campo das ciências biológicas (Freeman, 1998;Pena et al, 2000;Templeton, 1998).…”

Endless forms: human behavioural diversity and evolved universals

“…First, the very high behavioural diversity of Homo sapiens is not matched by a correspondingly high genetic diversity. In fact, it is just the opposite: our species has remarkably low genetic diversity for a large, widely dispersed mammal [3], even compared with other much less abundant and more localized species of hominoids, such as chimpanzees [4 -6].…”