Individual phenotypic data on six blood markers and six enzyme polymorphisms in seven Jewish and two non-Jewish populations were subjected to a comparative statistical analysis. A set of functionals defined with respect to the individual biochemical profiles was used to investigate the following problems: (1) What are the distributional characteristics of various types of individual heterozygosity measures (for blood and enzyme loci) within and across populations? (2) Is the observed phenotypic variation in agreement with what might be expected if the loci were independent? (3) What proportion of the characteristics can be explained by reference to population structure and historical data? Average total heterozygosity of blood and protein loci was highest in the Iraqi population and lowest in the Yemenite. The differences among the other populations were not significant. The highest cumulative recessive homozygosity of blood markers occurs in Yemenites and Samaritans. No association was present between total blood and protein heterozygosity. Applications of these ideas and techniques to the study of multilocus genetic organization are discussed.