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Lactase 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. Lactase is found in the brush border of the small intestine of humans and other mammals. People deficient in lactase or lacking functional lactase may experience the symptoms of lactose intolerance after consuming milk products. Microbial β-galactosidase can be purchased as a food supplement and is added to milk to produce "lactose-free" milk products.
Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, flatulence, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking something containing lactose, with the severity typically depending on the amount consumed. Lactose intolerance does not cause damage to the gastrointestinal tract.
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In archaeogenetics, eastern hunter-gatherer (EHG), sometimes east European hunter-gatherer or eastern European hunter-gatherer, is a distinct ancestral component that represents Mesolithic hunter-gatherers of Eastern Europe.
Sarah Anne Tishkoff is an American geneticist and the David and Lyn Silfen Professor in the Department of Genetics and Biology at the University of Pennsylvania. She also serves as a director for the American Society of Human Genetics and is an associate editor at PLOS Genetics, G3, and Genome Research. She is also a member of the scientific advisory board at the David and Lucile Packard Foundation.
References
- ↑ "UCL – University College London". 13 February 2019.
- ↑ Prof Mark Thomas Archived 2010-09-29 at the Wayback Machine , UCL School of Life and Medical Sciences
- ↑ "UCL – University College London". 13 February 2019.
- ↑ Hagelberg et al., 1994; Thomas et al., 2000a
- ↑ Thomas et al., 2000b.
- ↑ Weale et al., 2002.
- ↑ Thomas et al., 2006
- ↑ Charlotte A. Mulcare, Michael E. Weale, Abigail L . Jones, Bruce Connell, David Zeitlin, Ayele Tarekegn, Dallas M. Swallow, Neil Bradman and Mark G. Thomas (2004) The T allele located 13.9 kb upstream of the lactase gene (LCT) (C-13.9kbT) does not predict or cause the lactase persistence phenotype in Africans. [ permanent dead link ] American Journal of Human Genetics 74: pp1102–1110.
- ↑ J. Burger, M. Kirchner, B. Bramanti, W. Haak, M. G. Thomas (2007) Absence of the Lactase-Persistence associated allele in early Neolithic Europeans Archived 2008-10-31 at Archive-It . Proceedings of the National Academy of Sciences USA 104: pp3736-3741.
- ↑ Yuval Itan, Adam Powell, Mark A. Beaumont, Joachim Burger and Mark G. Thomas (2009) The Origins of Lactase Persistence in Europe [ permanent dead link ]. PLoS Comput Biol 5(8): e1000491.
- ↑ Powell, A., Shennan, S., and Thomas, M.G. (2009) Late Pleistocene Demography and the Appearance of Modern Human Behavior. Science 324: pp. 1298–1301
- ↑ Blood and Treasure [ permanent dead link ], The Economist, Jun 4th 2009
- ↑ "Brining to light patterns of migration from 6 000 to 500 BC". Community Research and Development Information Service (CORDIS).
