The neighbor joining (NJ) relatedness dendrogram based on HLA-DRB1 allele frequencies from the same study separated the various populations examined in the study in two well-differentiated clusters: the first cluster grouping North and South Mediterraneans (Europeans and Africans), Middle Easterners, Caucasians and western Siberians, and the second cluster grouping the rest of the analyzed populations (central and eastern Siberians and Orientals). Azerbaijanis were integrated in the first cluster, together with Gorgan (Iranian Turkmen population) and Kurds, and in an intermediate position between Iranian populations and western Siberians, namely the Chuvashes, Mansis, Buryats and Todja (Tozhu Tuvans). Correspondence analyses based on HLA-DRB1 allele frequencies showed similar results.