Homo sapiens who migrated to different parts of the world from Africa 80 thousand years ago had to face very difficult climatic conditions during their travels.
While their metabolism adapted to different climates during the evolutionary process, a feature that allowed them to cope with the cold did not develop equally for all Homo sapiens.
A new study published in the American Journal of Human Genetics has found that people who do not have the alpha-actinin-3 protein in their muscle fibers are more resistant to the cold.
A study by researchers at the Lithuanian University of Sports (LSU) found that 1 in 5 people do not have this protein and that these people are “very resistant to cold”.
1.5 billion people in the world do not have the alpha-actinin-3 protein. Scientists believe that this is due to a mutation in the ACTN3 gene that carries the protein codes.
Muscles are made up of many fibers that look like long steel cables. Proteins known as actin and myosin help to contract these muscle fibers.
Muscle fibers are divided into fast contractile fibers and slow contractile fibers, slow contractile fibers conserve energy, and fast contractile fibers use energy.
The alpha-actinin-3 protein is found in rapidly shrinking fibers.
Therefore, people who do not have the alpha-actinin-3 protein will be able to resist the cold thanks to the slower contraction fibers.
“Slowly contractile fibers effectively generate heat. Alpha-actin-3 protein deficiency does not cause tremors when exposed to cold. Instead, they conserve energy by increasing the number of muscles.”
The scientists said the findings also play an important role in the study of hereditary disorders such as muscular dystrophy.