Increased signaling of the Neanderthal growth hormone receptor.

Neanderthal-specific mutations in the growth hormone receptor increase signaling and are linked to greater muscle mass in some modern humans.

• Why it matters: Understanding genetic contributions to physical robustness helps reveal how ancient adaptations influence present-day human traits and health.
• What they did: The study analyzed Neanderthal GHR variants, finding two amino acid changes and a deletion; these variants enhance cell proliferation in response to pituitary GH and are present in some modern humans.
• The result: This increased signaling correlates with traits like increased muscle mass and Neanderthal-like craniofacial features, suggesting that ancient genetic variations continue to impact human physiology today.