ABO blood groups in medieval remains (Ras,Novi Pazar,X-XII A.D.)

Bone samples from a medieval cemetery (Ras, Novi Pazar, Serbia, X-XII A.D.) were serologically examined in order to determine ABO blood groups. The frequency of the AB blood group was much higher in the inhabitants of the medieval Ras than in the inhabitants of the Ras region of the 20th century. On the other hand, the incidence of the O blood group was smaller in the Ras population of the early Middle Ages. It was assumed that migrations which took place in that part of the Balkan Peninsula and Serbia influenced the distribution of ABO blood groups.