Genetic heterogeneity of prothrombin (FII)

A new procedure for the electrophoresis and localization of prothrombin is described. This technique has revealed three allelic variants at the prothrombin structural locus (FII). One of these alleles (FII4) reaches polymorphic frequencies in some Pacific Island populations. Investigation of the activated products of the three variant prothrombins has demonstrated that, in each case, the structural variation is located on a profragment and not on the enzymically active thrombin molecule.