In Yakut populations examined, polymorphisms of immunological and serum protein markers, including AB0 and Rhesus blood groups, HP, TF, GC, PI and C3, were revealed. Gene frequencies for the systems studied fell into the following ranges: AB0 system: r, 0.514 to 0.663; p, 0.136 to 0.306; q, 0.110 to 0.337; haptoglobin HP*1: 0.214 to 0.431; transferrin TF*C: 0.700 to 1.0; group specific component GC*1: 0.821 to 0.978; PI*M1 proteinase inhibitor (or alpha 1-antitrypsin) PIM1: 0.860 to 0.946; and third component of the complement C3*F: 0.031 to 0.143.