SEP 07, 2020 4:41 AM PDT

Lactose Tolerance Quickly Moved Through Europe

WRITTEN BY: Carmen Leitch

Researchers have found evidence that humans in Europe gained the ability to metabolize the lactose, the sugar in milk, after infancy. In this work, scientists extracted genetic material from the bones of people that died in a conflict that occurred around 1200 B.C. on the banks of a German river called the Tollense. Reporting in Current Biology, the researchers determined that only one of the eight individuals carried a genetic variant that gave them the ability to digest the lactose that's found in cow's milk.

"Of the present-day population living in this same area, around 90 percent have this lactase persistence," noted lead study author and population geneticist Professor Joachim Burger of Johannes Gutenberg University Mainz (JGU). "This is a huge difference when you consider that there cannot be many more than 120 human generations between then and today."

Other than a few genetic variants (like one for lactase persistence), the people that lived in the Tollense region have genomes that are similar to people living in today's northern Germany and Baltic Sea area.

"The only way to explain this difference between these Bronze Age people and those of today is very strong natural selection," noted study author and biologist Professor Daniel Wegmann of the University of Fribourg in Switzerland. "We conclude that over the past 3,000 years, lactase-persistent individuals had more children or, alternatively, those children had better chances of survival than those without this trait."

A strong selective advantage was found for this variant. "In each generation, lactase-persistent individuals have a six percent greater chance of surviving to reproductive age than non-lactase-persistent individuals," said Professor Joachim Burger.

In 2007, Burger's team found that very few people who settled down and began to farm in the area were lactase-persistent.

"It is astonishing that at the time of the battle at the Tollense, more than 4,000 years after the introduction of agriculture in Europe, lactase persistence in adults was still so rare," said Burger.

So why was it so advantageous for humans to be able to digest the sugar in cow's milk early in life?

"With milk being a high-energy, relatively uncontaminated drink, its ingestion may have provided greater chances of survival during food shortages or when supplies of drinking water were contaminated. Particularly during early childhood, in the years shortly after weaning, this factor often may have been decisive amongst prehistoric populations," Burger suggested.

The bones used in this study came from the Tollense Valley, which is the site of what's now considered to be the oldest battle in Europe. Archeologists have been studying this area for over a decade.

Not everyone can easily digest lactose. Learn more about lactose intolerance from the video.


Sources: AAAS/Eurekalert! via Johannes Gutenberg Universitaet Mainz, Current Biology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
DEC 05, 2020
Genetics & Genomics
Super-Spreader Events Promoted 2018-2019 Hantavirus Outbreak
DEC 05, 2020
Super-Spreader Events Promoted 2018-2019 Hantavirus Outbreak
We've all learned about super-spreader events over the past year, but occasions where a large group of people gathers an ...
DEC 13, 2020
Genetics & Genomics
Investigating the Many Nuclei in Muscle Cells
DEC 13, 2020
Investigating the Many Nuclei in Muscle Cells
Researchers led by Professor Carmen Birchmeier at the MDC have used a cutting-edge tool to learn more about different nu ...
DEC 24, 2020
Microbiology
A New, Infectious Strain of SARS-CoV-2 Emerges
DEC 24, 2020
A New, Infectious Strain of SARS-CoV-2 Emerges
The UK recently reported that it had detected a new variant of the SARS-CoV-2 pandemic virus, which causes COVID-19. Thi ...
JAN 01, 2021
Genetics & Genomics
Common Brain Disorder Has a Genetic Influence
JAN 01, 2021
Common Brain Disorder Has a Genetic Influence
It's thought that as many as one in one hundred people are born with a brain disorder known as Chiari 1 malformation, bu ...
JAN 06, 2021
Genetics & Genomics
Junk DNA Helps Control the Body Clock
JAN 06, 2021
Junk DNA Helps Control the Body Clock
Our bodies run on a kind of molecular clock, which helps regulate and time certain functions beyond just waking and slee ...
JAN 10, 2021
Microbiology
Some Bacteria Know the Time
JAN 10, 2021
Some Bacteria Know the Time
People, animals, and even plants are known to have biological clocks, and new work has revealed that free-living bacteri ...
Loading Comments...