Sentences with phrase «lactase persistence»

B. Hirbo, Maha Osman, Muntaser Ibrahim, Sabah A. Omar, Jilur Ghori, Suzannah Bumpstead, Jonathan K. Pritchard, Gregory A. Wary, Panos Delouckas (2006) Convergent adaptation in humans: the genetic basis of lactase persistence in Africa.

Earlier studies on DNA samples taken from European farmers from around 5000 BC revealed a low lactase persistence rate.

However, at least five populations in Europe, Saudi Arabia and East Africa have developed genetic mutations independently that allow them to produce lactase throughout their entire lives, a condition known as lactase persistence.

The selection for lactase persistence in humans happened at least four times, once in Europe and three times in Africa (Tishkoff et al., Nature Genetics 2007 Jan; 39 (1): 31 - 40), and the timing is remarkably correlated with adoption of pastoralism in those parts of the world.

About 7500 years ago in what is now Eastern Europe a genetic mutation occurred to the switch gene, creating a condition called lactase persistence, that is the gene did not turn off lactase production.

«But here's the thing,» says Sverrisdóttir, «if natural selection is driving lactase persistence evolution in a place where people have no problems making vitamin D in their skin, then clearly the vitamin D and calcium explanation (known as the calcium assimilation hypothesis) isn't cutting it.

Archaeologists and anthropologists have shown that lactase persistence evolved in pastoralist populations, and it is easy to see why; there's not a lot of point being able to digest lactose if you're not consuming milk.

So famine could have led to episodes of very strong natural selection favoring lactase persistence.

Sverrisdóttir and colleagues obtained DNA from the bones of early Spanish farmers and they couldn't find the mutation that causes lactase persistence in Europeans (LCT -13910 * T).

«Our research reveals that lactase persistence already developed during the Middle Ages in Central Europe but this was clearly not the case everywhere on the continent.»

To see how much natural selection was needed to drive lactase persistence up to today's frequencies in that Iberia, Sverrisdóttir contacted her colleague Professor Mark Thomas in London.

New palaeogenetic study based in Mainz and London sees development of lactase persistence as the result of a natural selection process

Why this trait — known as lactase persistence — has evolved so quickly has been something of a mystery.

This is usually genetically determined, and people with milk - drinking ancestry are far more likely to possess the gene (s) for lactase persistence (it takes just one copy to keep making lactase into adulthood).

Fermented dairy from from unpasteurised milk of grass fed animals is one of the most healthy traditional foods for some people, especially for those who have type B blood group or lactase persistence.

The spread of that culture had the effect of spreading the lactase persistence gene.

But there's a gene called the lactase persistence gene, which allows some people to digest milk.

Interestingly, these results contradict the previous research conducted on human remains from medieval Hungary, which exhibited a lactase persistence rate of 35 percent compared to 61 percent in the country today.

«The evolution of lactase persistence is one of the best known and most dramatic examples of recent human evolution One of the ironies of working in this area is that we know it happened but we still don't fully know why» says Sverrisdóttir.

However, the question remains as to when and where humans began to exhibit a similar level of lactase persistence to us today.

The latest study from the University of Zurich reveals a 72 - percent lactase persistence rate among the population of the medieval town of Dalheim in Germany between 950 and 1200 AD, which indicates that lactase persistence had already reached modern Central European levels (71 — 80 percent) around 1000 years ago.

Nowadays, lactase persistence is so prevalent among Europeans and European - descendent populations in America and Australian that, until very recently, lactose intolerance was considered an abnormality, deficiency or disease.

The earliest indications of lactase persistence to date were found among farmers in Spain during the Late Neolithic (approx. 3000 BC; 27 percent with lactase persistence) and Scandinavian hunter - gatherers (5 percent with lactase persistence).

Subsequent research has revealed that lactase persistence is actually the abnormal condition, resulting from the recent evolution of specific genetic mutations in certain populations.

The University of Zurich's study therefore suggests that the evolution of lactase persistence did not follow a single pattern throughout Europe and that genetic lactase persistence may have been common in Central Europe earlier than in Eastern Europe.

Lactase persistence is found at highest frequencies in southern Sweden and in Ireland.

The strongest signal of selection is at the allele responsible for lactase persistence, supporting the view that an appreciable frequency of lactase persistence in Europe only dates to the past four thousand years.

324/9: 15 Genetic and epigenetic factors affecting regulatory elements underlie lactose intolerance and lactase persistence.

The lactase persistence alleles are a classic example of convergence in humans, convergence that results from cultural shifts away from hunting and gathering towards animal domestication.

For instance, lactase persistence, or the ability to digest lactose into adulthood, is one of those changes that have happened within the last 8000 years.

Society often paints «lactose intolerance» as a rarity when actually it's the condition of «lactase persistence» that's uncommon.

Hollox, E. Evolutionary genetics: Genetics of lactase persistence — fresh lessons in the history of milk drinking.