One in five has a mutation that provides superior resilience to cold

(Karolinska Institutet) Almost one in five people lacks the protein α-actinin-3 in their muscle fibre. Researchers at Karolinska Institutet in Sweden now show that more of the skeletal muscle of these individuals comprises slow-twitch muscle fibres, which are more durable and energy-efficient and provide better tolerance to low temperatures than fast-twitch muscle fibres. The results are published in the scientific journal The American Journal of Human Genetics.