Аннотация:The ability to digest lactose in adulthood is caused by a genetic mutation that emergedfollowing the domestication of cattle approximately 10 000 years ago. However, manyadults retain primary lactase deficiency – the ancestral phenotype characterized bya decline in lactase enzyme activity after weaning. While the global prevalence of thiscondition is well-documented, reliable large-scale population data for Russia have beenlacking so far. Microarray genotyping of genetic markers now enables high-quality,up-to-date research covering representative samples from diverse ethnic groups acrossRussia’s regions