Distribution of the CCR5 gene 32-basepair deletion in West Europe. A hypothesis about the possible dispersion of the mutation by the Vikings in historical times

The chemokine receptor CCR5 constitutes the major coreceptor for the macrophage-tropic strains of HIV-1. A mutant allele of the CCR5 gene named Delta 32 was shown to provide to homozygotes a strong resistance against infection by HIV. The frequency of the Delta 32 allele was collected in 7328 noninfected unrelated individuals from 31 different European populations, and in Cyprus, Turkey, Daghestan, and North-Africa. The Delta 32 allele was found in all populations studied, with a mean frequency of about 8.0%. A north to south gradient correlating latitude with Delta 32 allelic frequencies was found (r = 0.795, p < 10(-9)), with highest allele frequencies in Nordic countries. We hypothesized that the <Delta>32 allele was disseminated in Europe by the Vikings during the eighth to the tenth centuries, because the most elevated values of this variant are actually found in their actual populations, and because they raided during the corresponding period in most European countries. Human Immunology 62, 933-936 (2001). (C) American Society for Histocompatibility and Immunogenetics, 2001. Published by Elsevier Science Inc.