a: an actually or potentially interbreeding group within a species; also: a taxonomic category (as a subspecies) representing such a group b:breed
: a category of humankind that shares certain distinctive physical traits
Term once commonly used in physical anthropology to denote a division of humankind possessing traits that are transmissible by descent and sufficient to characterize it as a distinct human type (e.g., Caucasoid, Mongoloid, Negroid). Today the term has little scientific standing, as older methods of differentiation, including hair form and body measurement, have given way to the comparative analysis of DNA and gene frequencies relating to such factors as blood typing, the excretion of amino acids, and inherited enzyme deficiencies. Because all human populations today are extremely similar genetically, most researchers have abandoned the concept of race for the concept of the cline, a graded series of differences occurring along a line of environmental or geographical transition. This reflects the recognition that human populations have always been in a state of flux, with genes constantly flowing from one gene pool to another, impeded only by physical or ecological boundaries. While relative isolation does preserve genetic differences and allow populations to maximally adapt to climatic and disease factors over long periods of time, all groups currently existing are thoroughly mixed genetically, and such differences as still exist do not lend themselves to simple typologizing. Race is today primarily a sociological designation, identifying a class sharing some outward physical characteristics and some commonalities of culture and history. See alsoclimatic adaptation, ethnic group, racism.