formed a $100 million, three-year plan to chart just such a map. It’s called the International HapMap Project, and beginning with several hundred blood samples collected from Nigeria, Japan, China, and the United States, it will use highly automated genomics tools to parse out the common haplotype patterns among a number of the world’s population groups … the HapMap, together with a series of powerful genomic tools developed over the last several years, will make it possible to spell out in great detail the genetic differences between peoples from different parts of the world. … Ultimately, all of genetics boils down to measuring the genetic variation in some population of people and comparing it to their characteristics and looking for correlations. That’s all genetics ever is.” And, adds Altshuler, the HapMap “is simply a tool to study genetic variation at unprecedented levels of accuracy and detail.” … They also found that how people categorized themselves—whether they called themselves black or white or Asian—correlated closely with the genetic categories. … Race, of course, already plays a huge role in how doctors diagnose and treat patients. Physicians are well acquainted with the idea that Caucasians with northern-European ancestry have higher rates of cystic fibrosis than Asians and blacks, while African Americans suffer from higher rates of hypertension and diabetes.

ALFRED contains allele frequency data on polymorphic loci for different human populations. As genetic polymorphisms, the common alleles at these loci must be considered normal variations. While it is a demonstrable fact that different populations have different frequencies of these alleles, most of the common alleles are present in most human populations. Many studies have shown that for any one genetic polymorphism most of the variations will occur among the individuals within each population because of the different genotypes. Only a small additional proportion of the global variation occurs as gene frequency differences among populations. Those differences, however, can illuminate evolutionary histories of human populations and may be especially relevant to design and conduct of biomedical research.

Does Race Exist? If races are defined as genetically discrete groups, no. But researchers can use some genetic information to group individuals into clusters with medical relevance … scientists have collected data about the genetic constitution of populations around the world in an effort to probe the link between ancestry and patterns of disease … about 10 percent of the variation distinguishes continental populations … Some polymorphisms do occur in genes, however; these can contribute to individual variation in traits and to genetic diseases. As scientists have sequenced the human genome (the full set of nuclear DNA), they have also identified millions of polymorphisms. The distribution of these polymorphisms across populations reflects the history of those populations and the effects of natural selection. … The frequency of the FY*O allele, which corresponds to the absence of Fy antigen on red blood cells, is at or near fixation in most sub-Saharan African populations but is very rare outside Africa … By looking at the varying frequencies of these polymorphisms, they were able to distinguish five different groups of people whose ancestors were typically isolated by oceans, deserts or mountains: sub-Saharan Africans; Europeans and Asians west of the Himalayas; East Asians; inhabitants of New Guinea and Melanesia; and Native Americans. They were also able to identify subgroups within each region that usually corresponded with each member’s self-reported ethnicity. … West Africans generally have polymorphism frequencies that can be distinguished from those of Europeans, Asians and Native Americans … Several of the polymorphisms that differ in frequency from group to group have specific effects on health … In these examples—and others like them—a polymorphism has a relatively large effect in a given disease

Neil Risch of Stanford University, a leader in the field of genetics, contends that race is helpful for understanding ethnic differences in disease and responses to disease. His position was prompted by an editorial last year in the New England Journal of Medicine asserting that “’race’ is biologically meaningless,” and one in Nature Genetics warning of the “confusion and potential harmful effects of using ‘race’ as a variable in medical research.”

1. In large part, the controversy stems from advances in DNA research streaming from the Human Genome Project—and trying to reconcile the fact that the pattern of DNA data differs among ethnic groups.
2. All humans have the bulk of their genetic heritage in common and possess the same set of genes.
3. But because of mutations—or changes in DNA —each gene comes in slightly different versions, and some of them are more common in one ethnic group than another.
4. These genetic differences often have medical significance—since some occur among genes that affect susceptibility to disease and the response to drugs.
5. For example, a mutation that causes hemochromatosis, a disorder of iron metabolism, is rare or absent among Indians and Chinese, but occurs in 7.5 percent of Swedes. Differences involving susceptibility to sickle cell anemia and lactose intolerance have been noted among ethnic groups and races.