A gene variant modern humans inherited from Neanderthals around 47,000 years ago still shapes body composition today, researchers at Karolinska Institutet report in Current Biology. The variant of the growth hormone receptor is found mainly in South and East Asia, and in some populations up to 24% of people carry it.
In laboratory experiments, cells carrying the Neanderthal version of the receptor grew 40% more when stimulated with growth hormone than cells with the most common modern-human version. In an analysis of data from just over 1.1 million adults, the variant was associated with an average of 285 grams more body weight — almost all of it muscle mass.
The effect was absent in more than 6,000 children aged 11 or younger, suggesting the difference emerges later, possibly during puberty. Carriers also had slightly shorter tooth roots and subtle differences in jaw shape that echo Neanderthal features.
"It is fascinating that a gene variant inherited from Neanderthals still affects people today," said lead researcher Hugo Zeberg. "But not even a Neanderthal growth hormone receptor can replace training," added co-author Miriam Berreiter. The study, published August 5, involved an international team including Svante Pääbo's group.
