laktaasipersistenssin

Lakataasipersistenssi, known in English as lactase persistence, is a genetic trait that allows individuals to continue producing lactase, the enzyme required to digest lactose, beyond childhood. In most mammals, lactase production declines after weaning, leading to lactose intolerance in adulthood. Human populations exhibiting lactase persistence maintain the ability to digest lactose throughout life, which historically facilitated the consumption of milk and dairy products.

The primary genetic basis for lactase persistence lies in regulatory variants near the LCT gene, particularly the -13910*T allele located upstream of the lactase gene in a region of the genome associated with the MCM6 gene. This allele enhances transcription of LCT in adult tissues, sustaining lactase activity. Other variants, such as -22018*A and -14010*C, have been identified in African and Asian populations, respectively, indicating multiple evolutionary origins.

Evolutionary pressures such as selective advantage from milk consumption during scarce food periods contributed to the rise of lactase persistence genes. In European, Middle Eastern, Caribbean and some African societies, frequencies of the -13910*T allele exceed 70%, correlating with long histories of pastoralism and dairy consumption. Conversely, in East Asian and Indigenous Australian groups, lactase persistence remains rare owing to different subsistence strategies and lower selection pressure.

Clinical relevance lies in diagnosing and managing lactose intolerance. Individuals lacking lactase persistence often experience gastrointestinal symptoms upon lactose intake. Dietary adaptations include lactose-free products, lactase supplements or choosing alternative calcium sources. Lactase persistence research also informs understanding of human evolution, nutrition, and gene‑environment interactions.