[Genogeographic primary hypolactasia in the Old World populations].

The geographic distribution of primary hypolactasia (i.e., the genetically determined (LACR), age-dependent decrease in lactase activity, which is phenotypically expressed as the intolerance to whole milk), was studied. Data on the distribution of primary hypolactasia and the LACR gene frequencies in populations of the Old World are analyzed, with special emphasis on LACR distribution in Russia. New data on populations of Kildin Saamis, Mordovian ethnic groups (Mokshas and Erzyas), Udmurtians, Komi-Permiaks, Komi-Zyrians (Komi-Izhem ethnographic group), Northern (Sos'va) Mansis, Northern Khantys, and Russians are described. Gene geographic maps of the LACR gene's distribution in populations of the Old World, Europe, and the Ural region were constructed. A map reflecting the amount of the original information on different regions and, therefore, the reliability of the gene geographic maps, is given. In Europe, the interpopulation diversity Gst of the LAC*R gene was significantly higher (0.169) than the average diversity of the European gene pool. The high variation was assumed to result from a potent differentiating selection that affects the gene for primary hypolactasia.