Increased signaling of the Neanderthal growth hormone receptor

Neanderthals had a robust build and distinctive skeletal features. The hypothalamic-pituitary-somatotropic (HPS) axis, with growth hormone (GH) as a central signaling molecule, plays a crucial role in regulating skeletal development. To explore whether Neanderthal-specific genetic variations in the HPS axis contributed to their physical robustness, we examined genes encoding the relevant receptors and hormones. We find that the Neanderthal growth hormone receptor (GHR) carried two amino acid changes and one deletion. When the Neanderthal GHR is expressed in a GH-dependent cell line, the cells proliferate faster than cells expressing the modern human GHR when stimulated by pituitary GH but not by placental GH. We also show that some present-day humans have inherited the gene encoding the Neanderthal GHR. These individuals tend to have more muscle mass and exhibit some craniofacial traits reminiscent of Neanderthals. Thus, aspects of Neanderthal anatomy live on in people today.