The genetic position of the autochthonous subpopulation of Northern Navarre (Spain) in relation to other basque subpopulations. A study based on GM and KM immunoglobulin allotypes.

GM and KM immunoglobulin (Ig) allotypes were tested in 118 autochthonous Basques from northern Navarre. The results are compared to those obtained for the same genetic markers in 6 other Basque subpopulations, 3 from Spain (Guipúzcoa, Vizcaya, and Alava) and 3 from France: Macaye, Saint-Jean Pied de Port, and Mauleon. The northern Navarrese appear genetically closer to the Alava and Saint-Jean Pied de Port subpopulations. The Basques present 3 GM haplotypes that are uncommon in Caucasian populations, suggesting that they have not been completely isolated either from Asian or African populations. The GM1,17 23' 10,11,13,15,16 north Asian haplotype was probably the first to be introduced into the Basque area. The GM1,17 23' 5* haplotype, considered an African genetic marker although also detected in Central Asia, would have reached the Iberian Peninsula through consecutive historic migrations from North Africa. The rare haplotype GM1,17 23 21,28 results probably from a genetic recombination or crossing-over between the 2 common haplotypes GM1, 17 23' 21,28 and GM3 23 5. It is also found with a low frequency in other neighboring regions and countries; but the possibility of its having been introduced through the main passage connecting western France and Spain during the Roman Empire and Middle Ages cannot be ruled out.