Primary Adult Lactase Deficiency: A Problem in Anthropological Genetics1


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    I would like to thank Cheryl Ritenbaugh, Steve Zegura, Hermann Bleibtreu, and F. S. Hulse for reading and commenting on an earlier draft of this paper.


Most human populations manifest high prevalences of primary adult lactase deficiency. The most notable exception is that populations deriving from northern and western Europe show high rates of lactase sufficiency in adults. The evidence supporting hypotheses of physiological adaptation and genetic etiology of the trait is discussed, and possible areas for further research are suggested.