Study Identifies a Neanderthal Gene Linked to Greater Muscle Mass in Modern Humans

The genetic legacy of Neanderthals continues to influence modern humans, according to a new study that identified a Neanderthal-derived variant of the growth hormone receptor associated with greater muscle mass and subtle differences in facial and skull structure.

The findings were published in the journal Current Biology.

An international team led by Hugo Zeberg of the Karolinska Institute and Philipp Gunz of the Max Planck Institute for Evolutionary Anthropology investigated a version of the growth hormone receptor that was common in Neanderthals but is absent in most modern humans.

Growth hormone plays a key role in regulating the development of muscles and bones. To exert its effects, the hormone must bind to a receptor located on the surface of cells.

Laboratory experiments showed that cells carrying the Neanderthal version of the receptor responded much more strongly to growth hormone. These cells grew approximately 40% more than cells carrying the most common modern human version of the receptor.

Modern humans inherited this genetic variant through interbreeding with Neanderthals around 47,000 years ago.

Today, the variant is most common among populations in South and East Asia. In some South Asian populations, up to 24% of people carry the variant, compared with only about 0.5% of Europeans.

The researchers analyzed genetic and health data from more than one million individuals and found that adult carriers had, on average, about 270 grams more muscle mass than non-carriers.

Interestingly, the difference was not observed during childhood. An analysis of more than 6,000 children found no association between the gene variant and growth up to the age of 11. The researchers suggest that its effects become more apparent during puberty, when growth hormone levels rise sharply.

The study also linked the variant to subtle differences in facial and dental anatomy. On average, carriers had a slightly shorter rear portion of the lower jaw and shorter tooth roots—features that are considered more characteristic of Neanderthals.

The researchers emphasized that this gene is only one of many genetic factors influencing human growth, body composition, and physical appearance. It cannot explain the overall anatomy of Neanderthals but provides further evidence that elements of their genetic heritage continue to shape modern humans tens of thousands of years after the two groups interbred.