POPULATION STUDIES IN NORTHERN SWEDEN .19. THE OROSOMUCOID POLYMORPHISM

Genetic polymorphism of orosomucoid (ORM1) was studied by isoelectric focusing in 3,817 conscripts and blood donors from the counties of Nor rbotten and Vasterbotten in northern Sweden. The individuals were dist ributed according to place of birth into 23 subpopulations. There was a significant heterogeneity between the 23 subpopulations with respect to the allele frequencies (p = 1.10(-8)). The ORM12 allele varied be tween 27 and 46%, and a clineal variation was observed with decreasing ORM12 allele frequencies in the northern direction. Significant corr elations were found between the frequencies of the ORM1 alleles and pr eviously studied Finnish and Saamish marker genes. The geographical va riation of ORM1 alleles was in close agreement with the pattern expect ed from the known mixture of Finns, Saamis, and Swedes in northern Swe den and further underlines the impact of ethnic heterogeneity on the g enetic differentiation of the north Swedish population.