Original sentence: "easily one-third of blacks have white DNA" she wonders why, in light of this, so much of the focus on tracing ancestry in the black community has focused on finding a link back to a region in Africa.A a music critic referred to her as "another White girl trying to sing Black.According to recent studies white americans rank non-americans as closer in social distance to them than their fellow black citizens.As a result of close to four hundred years of living alongside whites the majority of African Americans have white admixture.Debra Dickerson writes:.Despite the shared ancestry that blacks and whites have in the US, the one drop rule has served to polarize the US into two racial groups.Due to "passing for white" many white people also have African ancestry.During the transatlantic slave trade approximately 600,000 africans were brought to the United States.However many are questioning the legitimacy of the one drop rule.In an interview with Larry King Mariah said despite her physical appearance and the fact the she was raised primarily by her white mother she does not feel that she is white because of the effects of the one drop rule.Prior to revealing her ethnic background in 1992, many people thought she was white.She holds that in ignoring their white ancestors African Americans are denying their fully articulated multi-racial identities.The first Africans arrived on what is now the United states in 1619.The one drop rule created a bifurcated system of either black or either white regardless of a person's physical appearance.The one drop rule is  virtually unique to the  United States.The one drop rule is a historical term in the United States that holds that a person with any trace of non-white ancestry (however small or invisible) cannot be considered white.The peculiarity of the one drop rule is illustrated with the case of Mariah Carey.This contrasts with the more flexible social structures present in Latin America where there are no clear cut divisions between the various ethnicities.Today there are 37 million African Americans