Lactose which is the main carbohydrate of
the milk, is a disaccharide sugar derived from galactose and glucose. To be
able to digest it, lactase enzyme is required. In mammals, after the period of breast
breeding, the expression of this enzyme drops considerably, until it disappears.
In general, during adulthood mammals feel sick whenever they try to digest this
sugar .However, a mutation responsible for lactose tolerance aroused randomly
years ago. This change in the regulatory region of the lactose gene, turned out
to provide additional sustenance and source of water to ancient individuals that
depend on dairying. As is showed a distinct advantage in this kind of
population, the trait of lactase persistence during adulthood was eventually favored
by natural selection, first in Europeans. Still today, is considered one of the
strongest signals of selection within human genome variation.
Latest findings, October 21
We encourage you to watch the video!
Published in Nature Communications by the University College of Dublin (Ireland)
Researches from the University College and Trinity College of Dublin have revealed that our Eiropean ancestors remained lactose intolerance for 5000 years. This occurred after they began practicing agriculture and 4000 years after they started to make cheese among Central European Neolithic farmers.
The study has analyzed DNA extracted from the petrous bones of 13 individuals skulls from different eras, all of hem found buried in archaelogical sites in the Great Hungarian Plain. Regarding the results, the authors sugest that from the Neolithic to the Bronze and Iron age might have occurred significant changes in the genetics of these populations.
What is more, it took several years of experimentation with different bones of varying density and DNA preservation to discover that the inner ear region of the petrous bone in the skull, which is the hardest bone and well protected from damage, is ideal fro ancient DNA analysis in humans and any other mammals. For the first time, the percentage for the DNA yiels in the petrous bones was 183 times higher than in other bones, such as those from the teeth, fingers or ribs.
The exceptionally high percentage of DNA yield made it possible to scientists to check for known genetic markers, including lactose intolerance. Thus, they found that in all that time human pigmentation was modified, as transformed from hunters to farmers, but instead, they did not acquired lactose tolerance.
This means that thses ancient Europeans would have had domesticated animals like cows, goats and sheeps, but they would not yet have genetically develoved a tolerance for drinking large quantities of milk from mammals.
Researches from the University College and Trinity College of Dublin have revealed that our Eiropean ancestors remained lactose intolerance for 5000 years. This occurred after they began practicing agriculture and 4000 years after they started to make cheese among Central European Neolithic farmers.
The study has analyzed DNA extracted from the petrous bones of 13 individuals skulls from different eras, all of hem found buried in archaelogical sites in the Great Hungarian Plain. Regarding the results, the authors sugest that from the Neolithic to the Bronze and Iron age might have occurred significant changes in the genetics of these populations.
What is more, it took several years of experimentation with different bones of varying density and DNA preservation to discover that the inner ear region of the petrous bone in the skull, which is the hardest bone and well protected from damage, is ideal fro ancient DNA analysis in humans and any other mammals. For the first time, the percentage for the DNA yiels in the petrous bones was 183 times higher than in other bones, such as those from the teeth, fingers or ribs.
The exceptionally high percentage of DNA yield made it possible to scientists to check for known genetic markers, including lactose intolerance. Thus, they found that in all that time human pigmentation was modified, as transformed from hunters to farmers, but instead, they did not acquired lactose tolerance.
This means that thses ancient Europeans would have had domesticated animals like cows, goats and sheeps, but they would not yet have genetically develoved a tolerance for drinking large quantities of milk from mammals.
