Distributions of HLA class I alleles and haplotypes in Bulgarians--contribution to understanding the origin of the population.

In this study we present for the first time HLA class I allele and haplotype frequencies at DNA level in the Bulgarian population. HLA class I profile of Bulgarians has been compared to other European and Mediterranean populations of common historical background in order to clarify more precisely the origin of our population. Genetic distances, phylogenetic trees and correspondence analyses show that the Bulgarian population is more closely related to the Italian, the Mediterranean, the Armenian and the Romanian population than to the other East and West European population. This is further supported by the analysis of HLA class I haplotypes in Bulgarians. Most of them are also common in Europe. However their frequency pattern in Bulgarians is similar to the South European populations. The presence of some rare alleles and haplotypes indicated Asian genetic inflow. On the basis of HLA class I profile and supported by historical and anthropological data, we suggest that the Bulgarian population is characterized by the features of the Southern European anthropological type with some influence of other groups such as Asians, Turks, Armenians. Migrations and assimilation of many different ethnic groups are the major factor determining the genetic diversity of our population.