by Playfuls Staff |
14th December 2006
U.S. scientists say African and European adults' ability to digest milk comes from a trait arising [more] independently from the same cause.
The researchers say that ability -- known as lactase persistence -- is frequent in Northern Europeans, but less frequent elsewhere, and might have been a consequence of cattle domestication and a pastoralist lifestyle.
Previous work showed genetically, the ability could be attributed to variants controlling the expression of the gene encoding the enzyme lactase-phlorizin hydrolase, or LPH. That enzyme breaks lactose into more easily absorbed sugars such as glucose and galactose.
Sarah Tishkoff and colleagues at the University of Maryland asked whether the genetic basis of lactase persistence in certain East African pastoralist populations might be attributed to the same variants. They studied 470 lactase-persistent and lactase non-persistent individuals from Kenya, Tanzania and Sudan and found a significant association between lactase persistence and one variant that's very close in location to the LPH variant previously associated with the trait in Europeans.
Because other genetic markers in the same region differed between the two populations, the authors conclude the lactase persistent-associated LPH variants arose independently.
The research appears in the January issue of Nature Genetics.
© 2006 UPI
