Review of isoelectric focusing for Gc, PGM1, Tf, and Pi subtypes: population distributions.

Isoelectric focusing (IEF) as a method for differentiating macromolecules with minor differences in isoelectric points has demonstrated an increase in the degree of genetic polymorphisms of the blood. Studies over the last 5 to 6 years have shown that genetic marker systems such as transferrin (TF), phosphoglucomutase (PGM1), the vitamin D-binding globulin (GC), and A1 antitrypsin (PI) are a great deal more polymorphic than observed using conventional electrophoresis. Additional genetic variants have been detected or further defined in such systems as esterase D (ESD) and hemoglobin (HB) to name a few. The increased heterozygosity levels of these genetic marker systems identified by IEF have added to their value in forensic medicine and resulted in further resolution of racial and population affinities. IEF should prove to be a valuable anthropological tool for measuring population structure and genetic distances.