Evolution of lactase persistence: an example of human niche construction
Gerbault, PascaleResearch Department of Genetics, Evolution and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK
Liebert, AnkeResearch Department of Genetics, Evolution and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK
Itan, YuvalCoMPLEX (Centre for Mathematics and Physics in the Life Sciences and Experimental Biology), University College London, Physics Building, Gower Street, London WC1E 6BT, UK
Powell, AdamAHRC Centre for the Evolution of Cultural Diversity, Institute of Archaeology, University College London, 31–34 Gordon Square, London WC1H 0PY, UK
Currat, MathiasLaboratory of Anthropology, Genetics and Peopling History (AGP), Department of Anthropology and Ecology, University of Geneva, 12 rue Gustave-Revilliod, 1227 Geneva, Switzerland
Burger, JoachimInstitute of Anthropology, Johannes Gutenberg University, AG Palaeogenetik, SBII-2 Stock-Raum 02-333, Colonel Kleinmann-Weg 2, 55128 Mainz, Germany
Swallow, Dallas M.Research Department of Genetics, Evolution and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK
Thomas, Mark G.Evolutionary Biology Centre, Department of Evolutionary Biology, Uppsala University, Norbyvagen 18D, 752 36 Uppsala, Sweden
English Niche construction is the process by which organisms construct important components of their local environment in ways that introduce novel selection pressures. Lactase persistence is one of the clearest examples of niche construction in humans. Lactase is the enzyme responsible for the digestion of the milk sugar lactose and its production decreases after the weaning phase in most mammals, including most humans. Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation ( −13910 * T ) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East. Current estimates for the age of lactase persistence-associated alleles bracket those for the origins of animal domestication and the culturally transmitted practice of dairying. We report new data on the distribution of −13910 * T and summarize genetic studies on the diversity of lactase persistence worldwide. We review relevant archaeological data and describe three simulation studies that have shed light on the evolution of this trait in Europe. These studies illustrate how genetic and archaeological information can be integrated to bring new insights to the origins and spread of lactase persistence. Finally, we discuss possible improvements to these models.