Genes and enzymes in man.

If as is now thought most genes achieve their effects by directing the synthesis of enzymes, genetic variation will be largely reflected by enzyme diversity. Such enzyme diversity in human populations is illustrated by studies on the recently dis covered genetically determined polymorphisms involving red cell acid phosphatase, phosphoglucomutase, adenylate kinase, and placental alkaline phosphatase. Three of these polymor phisms were discovered in the course of investigating some 10 arbitrarily chosen enzymes in none of which there was any a priori reason to expect any degree of genetically determined variation. The findings thus suggest that genetically determined polymorphism may be a feature of a substantial number of human enzymes. They also indicate that there exists a very high degree of individuality in the enzymic constitution of normal and healthy people.