Abstract: Lactose intolerance is a prevalent condition characterized by the inability to digest lactose, a sugar in milk and dairy products, due to a deficiency in the lactase enzyme. This condition is influenced by genetic variations near the lactase gene (LCT), particularly single-nucleotide polymorphisms (SNPs) such as -13910 C>T and -22018 G>A, which are associated with lactase persistence. These genetic variants have undergone positive selection in populations with a history of dairy farming, such as Northern Europeans, some African, and Middle Eastern groups, allowing them to digest lactose into adulthood. The prevalence of lactose intolerance varies significantly across populations, with higher rates in groups without a history of dairy farming, such as Native Americans and East Asians. Symptoms include gastrointestinal complaints like bloating, gas, diarrhea, and abdominal pain following lactose consumption. The regulation of the LCT gene involves complex interactions with enhancer sequences and regulators like peroxisome proliferator-activated receptor gamma (PPARγ). Future treatments may include gene editing technologies and modulation of the gut microbiome. Understanding genetic and environmental factors can inform personalized nutrition recommendations and public health strategies, highlighting the dynamic interplay between genes and environment in lactose intolerance Keywords: lactose intolerance, lactase persistence, LCT gene, genetic diagnosis, genetic variations, gene-environment interaction. Title: Understanding the Genetic and Evolutionary Basis of Lactase Persistence in Human Populations: A Comprehensive Review Author: Jintapong Zuercher Thammachai, Shinnattapol Songpholratchanon, Pune Phetra, Kittanath Limphotong, Chananchida Dussadeethommo, Yadasiri Rachatasitikul, Kanat Likittananan, Phatchara Tangtongchit, Vathunya Chudhakorn International Journal of Healthcare Sciences ISSN 2348-5728 (Online) Vol. 12, Issue 1, April 2024 - September 2024 Page No: 114-128 Research Publish Journals Website: www.researchpublish.com Published Date: 02-September-2024 DOI: https://doi.org/10.5281/zenodo.13626692 Paper Download Link (Source) https://www.researchpublish.com/papers/understanding-the-genetic-and-evolutionary-basis-of-lactase-persistence-in-human-populations-a-comprehensive-review