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When these enzymes are produced in low quantities, lactase non-persistence (LNP) results. [38] The ability to digest fresh milk through adulthood is genetically coded for by different variants which are located upstream of the LCT gene and which differ among populations. Those variants are found at very high frequencies in some populations and ...
However, most people worldwide remain lactase non-persistent. [9] Populations that raised animals not used for milk tend to have 90–100 percent of a lactose intolerant rate. [80] For this reason, lactase persistence is of some interest to the fields of anthropology, human genetics, and archaeology, which typically use the genetically derived ...
Lactase (EC 3.2.1.108) is an enzyme produced by many organisms and is essential to the complete digestion of whole milk.It breaks down the sugar lactose into its component parts, galactose and glucose.
The majority of humans actually follow this protocol as well, and down-regulate lactase production around 3-5 years of age. Interestingly, though, the majority of caucasians, mainly those from northern european background, continue to have elevated lactase activity all the way into adulthood, and so they exhibit “lactase persistence”.
New research indicates that famine and exposure to infectious disease best explains the evolution of our ability to consume milk.
However, 5% to 90% of the human population possess an advantageous autosomal mutation in which lactase production persists after infancy. The geographic distribution of lactase persistence is concordant with areas of high milk intake. Lactase non-persistence is common in tropical and subtropical countries.
Diploid organisms (e.g., humans) contain two copies of each gene—a paternal and a maternal allele. Based on the occurrence of mutation on each chromosome, we may classify mutations into three types. A wild type or homozygous non-mutated organism is one in which neither allele is mutated. A heterozygous mutation is a mutation of only one allele.
Lactase persistence One of the best known examples is the prevalence of the genotype for adult lactose absorption in human populations, such as Northern Europeans and some African societies, with a long history of raising cattle for milk.