People who carry a Neanderthal version of the growth hormone receptor have, on average, 271 additional grams of muscle compared with those who don’t. People who inherited the variant from both parents tend to have more still. The finding comes from a study that cross-referenced lab experiments with population data from more than one million people.
The growth hormone receptor is a cell protein that helps regulate growth throughout the body. When researchers compared modern human and Neanderthal genomes, they found distinct genetic changes in the Neanderthal version. In cell cultures, the Neanderthal receptor produced more growth than the modern human version, which fits with Neanderthals’ famously robust build and suggests the effect has carried forward into some modern human bodies.
Where the variant is most common
The variant is not rare. Most people alive today carry between one and two percent Neanderthal DNA, the result of interbreeding between modern humans and Neanderthals. This particular growth hormone receptor variant shows up most in South and East Asian populations, reaching up to 24 percent in some parts of South Asia.
What makes this study stand out
Lab findings and population data don’t always land on the same result. Here they did. “It is rare to see laboratory and population evidence fit together so clearly,” said Philipp Kanis, first author of the study and a postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “Cells grown in the laboratory responded more strongly, while data from more than a million people showed signs of the same effect in the body.”
Researchers are still working out how much of modern human biology traces back to Neanderthal ancestry. Effects on the immune system are one of the clearer examples documented so far. Muscle mass may now be another.
Miriam Berreiter, a co-author and Ph.D. student at the Karolinska Institute in Sweden, kept the finding in perspective: “Even a Neanderthal growth hormone receptor is no substitute for training.”
Source study: Current Biology– “Increased signaling of the Neanderthal growth hormone receptor“
