PERSONALITY GENETICS

Although 30-60% of the variance in many personality traits is inherite d, until recently little was known about the responsible genes. Prelim inary studies of family history in bipolar disorder and of X-linkage o f personality traits in color-blindness suggested a ''quantitative tra it locus'' (QTL) approach to the genetics of normal personality. Ln me thodically similar but independent studies of 124 Israeli and 315 Amer ican normal volunteers we showed an association between the dopamine D 4 receptor gene (D4DR) and the personality trait of novelty seeking. I n the Israeli sample we also found an interaction between the D4DR gen e and the serotonin 2C receptor gene (5-HT2C) with a marked effect on the trait of reward dependence. Further investigation of genes for per sonality traits may suggest Links between normal personality and psych iatric illness.