Both traits evolved to help the ancestors of these groups resist malaria infection, but both prove lethal when inherited in a double dose. As with differences in skin pigmentation, the means to do so was through the alteration of a single gene. Another cause of group differences is the so-called founder effect. In such cases, the high prevalence of an unusual condition in a population can be traced to a founding ancestor who happened to carry a novel mutation into the region. Dr. Sonia S. Anand, an assistant professor of medicine at McMaster University in Ontario, proposed that clinicians think about ethnicity rather than race when seeking clues to how disease patterns differ from one group to the next.
Ethnicity is a broad concept that encompasses both genetics and culture.
Thinking about ethnicity is a way to bring together questions of a person's biology, lifestyle and diet. Ethnicity is about phenotype and genotype, and it allows people to look at differences between groups in another way. However, studying the effects of racial labeling is imperative and a prerequisite to correcting the errors of the past. In investigating the reasons behind the high incidence of cardiovascular disease among people from the Indian subcontinent, for example, Dr. Anand discovered that Indians had comparatively elevated amounts of clotting factors in their blood. Beyond tallying up innate traits, she also takes into account how Indian culture and life habits may pose added risks for heart disease.