A specific gene inherited from Neanderthals appears to increase muscle mass in modern humans, according to research from the Max Planck Society. This genetic mutation, passed down through interbreeding approximately 47,000 years ago, affects how cells respond to growth hormone, leading to greater muscle development.
Individuals who inherit one copy of this Neanderthal gene gain an average of 270 grams of muscle. Those who inherit two copies, one from each parent, gain about half a kilogram more muscle mass on average. The mutation is also associated with wider hips and jawline characteristics reminiscent of Neanderthals.
How the Gene Works
The Neanderthal variant impacts the body's growth hormone receptors. Growth hormone, produced by the pituitary gland, signals cells to grow. To do this, it must bind to a receptor on the cell's surface. The Neanderthal receptor variant is more efficient, meaning it produces a stronger cellular response even with the same amount of growth hormone. Lab tests on engineered cells showed that those with the Neanderthal receptor grew approximately 40% faster than cells with the modern human variant.
This enhanced response is particularly noticeable during puberty, a period of rapid growth. While Neanderthals were known to be more robust and muscular than early Homo sapiens, this gene is just one of many factors contributing to physical morphology.
Genetic Distribution and Implications
The presence of this gene varies significantly across populations. Up to 24% of people in South Asia carry the trait, while only about 0.5% of modern Europeans do. The gene is largely absent in people of African heritage, as it was acquired after early humans migrated out of Africa.
Researchers suggest the high prevalence in South Asia might indicate an advantage conferred by the gene, though other factors like the 'founder effect' could also explain its concentration. Despite the increased muscle mass, scientists do not believe this Neanderthal trait makes individuals inherently better athletes, as overall strength is influenced by a multitude of genetic and environmental factors. Training remains a primary determinant of physical performance.