Genetic Adaptation of Fat Metabolism Key to Development of Human Brain

About 300,000 years ago, humans adapted genetically to be able to produce larger amounts of omega-3 and omega-6 fatty acids. This adaptation may have been crucial to the development of the unique brain capacity in modern humans. In today's life situation, this genetic adaptation contributes instead to a higher risk of developing disorders like cardiovascular disease. The human nervous system and brain contain large amounts of polyunsaturated fatty acids, and these are essential for the development and function of the brain. These omega-3 and omega-6 fatty acids occur in high quantities in just a few foods, such as fat fish. Our bodies can also produce these important fatty acids themselves from certain vegetable oils. In a new study led by researchers at Uppsala University in Sweden and published April 12, 2012 in The American Journal of Human Genetics, scientists have investigated the genes for the two key enzymes that are needed to produce omega-3 and omega-6 fatty acids from vegetable oils. They have found that humans have a unique genetic variant that leads to increased production. This genetic adaptation for high production of omega-3 and omega-6 fatty acids is found only in humans, and not in our living primate relatives chimpanzees, gorillas, and rhesus monkeys. Neanderthals or Denisovans, another type of extinct hominin species, also did not have this genetic variant. It appeared some 300,000 years ago in the evolutionary line that led to modern humans. This genetic adaptation for more efficient omega-3 and omega-6 production from vegetable oils developed in Africa and has probably been an important factor for human survival in environments with limited dietary access to fatty acids.
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