This chapter examines "race," "ancestry," and "cultural identity," and suggests that it is important to examine whether each necessarily reflects the others. Studies of genetic variation in African-American populations have further demonstrated the imprecise relationship between genetics and cultural identity. Genetic ancestry therefore varies as one looks across each chromosome, and different regions of the genome are derived from different genealogical ancestors. Genetic ancestry testing moves the quest for "reflections of our past" from the level of species and population to the level of the family and individual. The concept of race first emerged with European colonialism and the rise of the transatlantic slave trade, as a way to sort, classify, and rank the diverse human populations that European explorers were encountering. This biological race concept emphasizes the importance of geographically structured genetic variation, suggesting that races are discrete geographic subdivisions of the human species that are genetically distinct.