Modern humans with non-African ancestry carry a Neanderthal growth hormone receptor variant that increases muscle mass and alters bone structure, according to a study published in Current Biology. Led by the Max Planck Institute for Evolutionary Anthropology, researchers found this genetic legacy persists in roughly 20% of some South and East Asian populations.
Neanderthal DNA and the Growth Hormone Receptor
Neanderthals disappeared roughly 42,000 years ago, but their biological influence remains. Researchers from the Max Planck Institute for Evolutionary Anthropology identified a specific version of the growth hormone receptor—a protein regulating how the body responds to pituitary growth hormones—that differs from the version found in sub-Saharan Africans.
This variant features two amino acid changes. In laboratory tests, cells equipped with the Neanderthal receptor multiplied faster and exhibited stronger downstream signaling than those with the modern human version, according to the study team.
Did you know? People with non-African roots carry approximately 2% Neanderthal DNA due to interbreeding that occurred primarily 47,000 years ago, though some evidence suggests earlier admixture events.
Physical Effects on Muscle Mass and Jaw Structure
The research team analyzed genetic and health data from over one million people across several biobanks to see how this gene manifests in living adults. They found that carriers of the Neanderthal variant tend to be slightly taller and heavier.
The additional weight is attributed primarily to increased muscle mass rather than body fat. Beyond weight, the variant correlates with specific skeletal traits: a shorter mandibular ramus (the vertical part of the jawbone), a higher frequency of overbites, and shorter tooth roots. These characteristics mirror the robust anatomy seen in Neanderthal fossils.
The Role of Puberty in Genetic Expression
The study noted that these physical differences are not detectable in children. Dr. Philipp Kanis and his colleagues suggest these traits emerge around puberty, coinciding with the period when growth hormone levels in the human body rise sharply.
Comparing Evolutionary Lineages
Neanderthals evolved in isolation from modern humans for half a million years, appearing in the fossil record between 300,000 and 400,000 years ago. Their distinctive anatomy included prominent brow ridges, an occipital bun at the back of the skull, and a barrel-shaped thorax.
| Trait | Neanderthal Characteristic | Modern Carrier Effect |
|---|---|---|
| Muscle/Build | Robust bodies, high muscle mass | Slightly heavier, more muscle mass |
| Dental/Jaw | Short-rooted teeth (taurodontism) | Shorter tooth roots, overbite likelihood |
Limits of Genetic Influence
While the laboratory and population data align, researchers emphasize that this single gene is not a blueprint for a Neanderthal appearance. Dr. Hugo Zeberg of the Max Planck Institute stated that this is only one of many genetic influences on body shape and cannot determine a person’s overall appearance on its own.
Pro Tip: To learn more about how ancestral DNA affects modern health, explore peer-reviewed journals like Current Biology.
Frequently Asked Questions
Do all humans have Neanderthal DNA?
No. According to the study, the variant is rare or absent in sub-Saharan African populations, as they had little to no Neanderthal ancestry.
Does this gene make someone look like a Neanderthal?
No. While it contributes to traits like increased muscle mass or shorter tooth roots, Dr. Hugo Zeberg notes it does not determine a person’s overall appearance.
When do these traits become visible?
The researchers found that the differences are generally not detectable in children, emerging instead around puberty.
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