Ancient Neanderthal DNA and Muscle Mass

Researchers led by Hugo Zeberg of Karolinska Institutet and Philipp Kanis of the Max Planck Institute for Evolutionary Anthropology discovered that a Neanderthal-derived growth hormone receptor carried by some modern humans amplifies growth-related signals in cells by 40 percent. Published on August 13, 2026, the study reveals that interbreeding about 47,000 years ago introduced this variant into modern human gene pools, where up to 24 percent of people in certain South Asian populations and 0.5 percent of Europeans currently carry it. The authors emphasize the robust convergence of laboratory cell assays and population data from over a million individuals, demonstrating that this genetic variant correlates with an average increase of about 270 grams of muscle mass in adult carriers, along with subtle differences in skull shape and shorter tooth roots. The research highlights how specific archaic genetic traits continue to exert measurable physiological impacts on contemporary human biology without solely dictating overall physical appearance. The scientific investigation details how growth hormone produced by the pituitary gland attaches to cell surface receptors, with the Neanderthal variant containing two unique amino acid changes absent from typical modern receptors. Laboratory tests confirm that these structural alterations enhance intracellular signal transmission, leading to significantly amplified growth responses when stimulated by growth hormone. Practical applications of these findings provide deeper insights into human evolutionary genetics, pediatric endocrinology, and muscle physiology. Because the trait's effects manifest post-childhood and near puberty when growth hormone levels surge, researchers can better understand the multifactorial genetic architecture controlling human body shape, metabolic traits, and musculoskeletal development.