Best estimates are that anatomically modern humans migrated from Africa approximately 65,000 to 25,000 years ago

All current human populations are descended from those individuals

Because of our recent descent from common ancestors, there has been a small amount of evolutionary time for diversity to arise in human populations

Current African-Americans are descended both from African slaves and from other groups—Europeans , Native Americans, etc.

As a result, there is much genetic diversity within ethnic groups and much similarity between groups

Notions of “race” vary according to time and place

In the 19th century you were a “negro” if 1/8 of your family inheritance was from slaves

In the 2000 census 14 million Americans listed themselves as belonging to at least two races

Is Barak Obama black? Who gets counted as

belonging to what group reflects a complex social labeling process

Race is in this sense “socially constructed”

A common justification for slavery was that blacks were biologically, innately inferior

Scientists in the 19th and 20th centuries supported eugenics

Eugenics is the practice of restricting who gets to have children to improve the human species

PK Welpton, a demographer, said in 1938:

“Ancestry” denotes those in the past that you are biological related to

Differences in ancestry can result in genetic differences

It is possible to measure genetic ancestry in various ways

Some stretches of DNA –SNPs--are relatively uncommon across the world’s populations but can be unique to some subpopulations

These are called AIMs—ancestry informative markers

Researchers have collected AIMS distinctive of West African, Northern European, Native American, and other populations

These allow a blood sample of a current individual to be tested to determine what proportion of his or her genes might come from those populations

National Institutes of Health grant reviewers have recently rejected grant proposals for admixture studies in part because they fear reinforcing stereotypes

A recent NY Times article identified racist web sites citing admixture results

Racial prejudice still exists and public understanding of genetics is poor

Does this justify censoring potentially important scientific findings?