New research has found one in five people have a specific genetic mutation that confers greater resilience to cold temperatures. The experimental study shows how people with a deficiency in generating a certain skeletal muscle protein shiver less and hold a higher core temperature in cold environments.
Recent genomic studies have suggested about 20 percent of people have a novel mutation in the ACTN3 gene, which expresses a skeletal muscle protein called alpha-actinin-3. This protein is found in greater volumes in fast-twitch muscle fibers.
The mutation in ACTN3 leads to a deficiency in alpha-actinin-3, increasing the prominence of slow-twitch muscle fibers. Evolutionary biologists have previously tracked the appearance of this mutation in humans as people migrated out of Africa into Europe and Asia.
Exactly what purpose this particular mutation served has been unknown but some researchers have hypothesized it as possibly helping early humans adapt to the colder climates of Europe. A new international study set out to empirically test that hypothesis.