DETECTION AND ANALYSIS OF THE HUMAN D4 DOPAMINE-RECEPTOR GENE (DRD4) SEQUENCE VARIANT IN THE JAPANESE AND MONGOLIAN POPULATION

A PCR-based Sma I restriction fragment length polymorphism (RFLP) in t he human D4 dopamine receptor (DRD4) gene was investigated in 200 subj ects each of Japanese and Mongolian populations. When compared to alle le frequencies for Caucasians previously reported by Petronis et al., Japanese and Mongolian populations showed a decreased frequency of the allele which could not be digested with Sma I. The difference in alle le distributions between these two ethnically defined populations (Jap anese and Mongolians, and Caucasians) was statistically significant (p <0.05). This RFLP was suggested to be a racial difference between Asia n and European populations. However, since the frequency of the non-di gested allele was extremely low (1%) in the Asian populations, we cann ot exclude the possibility that this allele represents a mutation. Sma I PCR-RFLP typing would not only be one of genetic markers, but might also be a specific marker for searching some neuropsychiatric abnorma lities. (C) 1996 Academic Press, Inc.