Ancient Neanderthal Variant Still Shapes Muscles and Jaws in Modern Humans

A study comparing modern and Neanderthal genomes found a Neanderthal variant of the growth hormone receptor that enhances growth signaling and persists in non-African populations, especially in some South and East Asian groups where about 20% carry it. Carriers tend to be taller and heavier due to increased muscle mass, and exhibit Neanderthal-like jaw traits (shorter mandibular ramus, higher overbite, shorter tooth roots). Effects emerge around puberty, with lab experiments showing faster cell growth and stronger signaling in cells with the Neanderthal receptor. The variant is one of many factors influencing body shape and is not the sole determinant of the modern human physique.