What is new concerns the particularity of this knowledge, and its implications for human performance. Scientists at the Sanger Center near Cambridge, England recently announced that they had completed the genetic sequencing of human chromosome 22, one of the 23 paired structures that collectively contain the entire human nuclear gene complement. While all humans share the same basic set of chromosomes, and hence the genetic loci arrayed along them, at numerous loci there are so many variants that each of us represents a unique and special draw from the common gene pool. The extent of this human genetic diversity has been known in general terms since at least the 1970s. Consider the function of the several apolipoprotein genes.
Lipoproteins carry triglyceride fats and cholesterol in the blood.
These APOE genes vary in frequency among the world's populations. The 4 percent of people who have two copies of the E2 gene are especially sensitive to diets rich in fat and cholesterol, on which they are ready candidates for heart disease, as are those with two copies of E4. Frequency differences also have implications for the interplay of human genetics and behavior in shaping individual risk profiles during various sports. Among professional boxers, one in six gets Parkinson's or Alzheimer's disease. The microscopic symptoms of these disorders are similar, though predispositions to them appear to have different genetic bases.