The relations between G-6-PD deficiency, thalassemia and malaria. Further analysis of data from Sardinia and the Po Valley.

Discriminant analysis carried out on a set of environmental and sociocultural variables in the Sardinian population suggests that G-6-PD deficiency and thalassemia move along 2 dimensions partially independent of each other. Partial correlation analysis also suggests that malaria, by itself, may exert opposite effects on thalassemia and G-6-PD selection. The present results support the hypothesis that thalassemia may be the primary genetic factor selected by malaria, whereas G-6-PD selection may be a secondary adaptation phenomenon strongly dependent on other genetic and environmental variables.