Though humans are known to lose lactase ability post-weaning, some people maintain lactase production into adulthood, a condition known as lactase persistence. Global distribution patterns of lactase persistency are inconsistent; the condition is much more prevalent in some populations than others. Using results across independent studies, the existence of such a phenomenon can be attributed to positive selection on ancestral pastoralist populations. Two different hypotheses explain this positive selection: milk-independent economies, and colonic bacteria adaption.
Digital Object Identifier
Du, Xinghan (Hill) and Gray, Patricia M.
"Evolutionary GEM: Evolution of Lactase Persistence,"
WURJ: Health and Natural Sciences: Vol. 8
, Article 29.
Available at: https://ir.lib.uwo.ca/wurjhns/vol8/iss1/29