Population studies of human deoxyribonuclease I polymorphism

We have improved the resolution of the conventional method for phenotyping deoxyribonuclease I (DNase I), which makes use of isoelectric focusing, by the addition of amphoteric separators. The distribution of DNase I phenotypes was extensively examined using this improved method in 1,212 unrelated individuals from a Japanese population. In order to investigate a possible difference in phenotype distribution between different populations, DNA samples from Germans and African Americans were genotyped using the polymerase chain reaction. The DNASE1*2 allele in the German population was found to be predominant among the four alleles of DNase I, in contrast to the Japanese population. These results are the first to demonstrate a wide distribution of DNase I polymorphism in the Japanese population as well as in two other populations.