A recent study published in Science shows that the Greenlandic Inuit population suffered genetic mutations that helped them counteract the side effects of their heavy in fats diet, which is mostly based on fish and marine mammals.
Evolutionary biology is a captivating field. The best experiments according to evolutionary biologists are those that are already taking place in nature, such as the different conditions that made us adapt and change throughout tens of thousands of years. The new study’s findings show exactly that in the adaptive mechanisms Greenlandic Inuits developed.
The research could help us understand just to what degree genetic diversity could impact our health through diet. It could also help us devise personalized diets based on our genetic background, depending on variables such as race or location.
Some of the strongest existing evidence of diet impact on natural selection has been documented in statistics that deal with the lactase gene, the gene that helps us digest lactose from milk. For instance, T. Colin Campbell’s best-seller called The China Study made strong points on how the lactase gene can differ from a region to another.
The ability to digest the lactose in milk generally disappeares after growing out of childhood. In rare cases however, it can persist into adulthood if the individual carries a specific genetic variant. Those persons take advantage of this mutation as a means to get more nutrition from dairy compared to those that lack the selective advantage.
The individuals who have this kind of genetic mutations are more likely to survive than the rest of the population, and procreate healthier children who will inherit this ability as well. Over time, evolution’s “survival of the fittest” rule will help people with the said capability of digesting such food breed more efficiently, rendering them over-represented in the human population.
Thanks to statistical approaches, these kind of genetic patterns can be found and analzyed by evolutionary biologists. This particular study gathered data from 190 people with Inuit ancestry, then they compared their genomes to the genomes of 100 other people from Europe and East Asia.
What the scientists have found is that Inuit’s shorter height is explained by the selective mutations associated with cholesterol and insulin breakdown, which protects them against cardiovascular disease and diabetes. The link between their height and fatty acid diet is more obvious in their growth hormone regulation. Because the European population lacks the mutation that allows them to eat high intakes of fish oil and omega-3, they are with about four centimeters taller than the Inuit population.
Researchers estimate that this genetic selection began to establish itself in the Greenlandic Inuit population about 20,000 years ago.
Photo credits: 1