Human populations living today share a specific genetic legacy from ancient interbreeding events, according to a study led by researchers Hugo Zeberg of Karolinska Institutet and Philipp Kanis of the Max Planck Institute for Evolutionary Anthropology. Modern humans inherited a variant of the growth hormone receptor through interbreeding with Neandertals around 47,000 years ago, resulting in measurable differences in muscle mass, bone structure, and regional population distribution across the globe today.
Neandertal Variant Shows Stronger Response to Growth Hormone
Growth hormone regulates the growth of muscles and bones by traveling through the bloodstream from the pituitary gland to bind with cell surface receptors. According to findings published in Current Biology, laboratory-grown cells utilizing the Neandertal version of this receptor responded 40 percent more strongly to growth hormone than cells carrying the common modern human version. Researchers traced the majority of this heightened cellular response to one specific genetic change out of two distinct alterations found in the ancient receptor variant.
Did you know? Up to 24 percent of people in certain South Asian populations carry the Neandertal growth hormone receptor variant, compared to approximately 0.5 percent of individuals in European populations.
Post-Childhood Effects on Adult Muscle Mass and Skull Structure
The physiological impact of the inherited receptor variant appears primarily after early development concludes. An examination of body measurements from more than 6,000 children showed no discernible link between the Neandertal receptor version and growth patterns up to the age of eleven, according to the study data. Researchers suggest the effects materialize later in life, potentially coinciding with puberty when natural growth hormone levels increase significantly. Among adult carriers, the genetic variation correlates with an average increase of roughly 270 grams of muscle mass.
Beyond musculature, the genetic variant influences specific skeletal features. Carriers exhibit subtle differences in the skull and teeth, including a slightly shorter rear section of the lower jaw and shorter tooth roots. These anatomical traits align closely with characteristics typical of Neandertal morphology, demonstrating how a single inherited genetic modification continues to shape contemporary human biology.
Frequently Asked Questions
How common is the Neandertal growth hormone receptor today?
The variant is most prevalent in South and East Asia, where up to 24 percent of people in certain South Asian populations carry it. In contrast, only about 0.5 percent of Europeans carry the same version.
Does carrying the Neandertal receptor guarantee a muscular physique?
No. As noted by study co-author Miriam Berreiter, the Neandertal growth hormone receptor is no substitute for training.
When do the physical effects of this genetic variant become noticeable?
Data from more than 6,000 children showed no link between the receptor version and growth up to age eleven, indicating that effects likely emerge later, such as during puberty.
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