A new study of hundreds of human genomes has revealed that groups in various regions of the world have evolved for diets with different amounts of meat and vegetables. People from Europe, particularly its southern regions, are optimized for a high-plant diet. But people from other areas, such as the Inuit of Greenland, have a biochemistry that is better able to process lots of meat fat.
The study, which appeared in Molecular Biology and Evolution, would not have been possible without recent advances in ancient genome sequencing. UC Berkeley Integrative Biology professor Rasmus Nielsen and his colleagues had access not only to hundreds of genome sequences from humans today, but also to sequences from 101 people who lived in Europe 5,000 years ago during the Bronze Age. By comparing these genomes, they found that two particular regions of DNA were under intense selection over the past several thousand years and changed rapidly in response to evolutionary pressures.
These DNA regions contain two genes called “fatty acid desaturase 1 and 2,” or FADS1 and 2 for short. The FADS genes regulate how the human body converts short-chain poly-unsaturated fatty acids (PUFAs) into long-chain PUFAs for the health of many tissues, including muscles and the brain. In Europeans dating back to the Bronze Age, the FADS genes have undergone mutations to produce more long-chain PUFAs. This suggests a diet higher in vegetables and grains, which produce short-chain PUFAs. Meat produces long-chain PUFAs. The Inuit group’s FADS genes are primed to produce fewer long-chain PUFAs, likely because the Inuit diet is so high in animal fats from ocean mammals.