Abstract
The enzyme AMPD1 is expressed in skeletal muscle and is involved in ATP production. All available Neandertal genomes carry a lysine-to-isoleucine substitution at position 287 in AMPD1. This variant, which occurs at an allele frequency of 0-8% outside Africa, was introduced to modern humans by gene flow from Neandertals. Here, we show that the catalytic activity of the purified Neandertal AMPD1 is ~25% lower than the ancestral enzyme, and when introduced in mice, it reduces AMPD activity in muscle extracts by ~80%. Among present-day Europeans, another AMPD1 variant encoding a stop codon occurs at an allele frequency of 9-14%. Individuals heterozygous for this variant are less likely to be top-performing athletes in various sports, but otherwise reduced AMPD1 activity is well tolerated in present-day humans. While being conserved among vertebrates, AMPD1 seems to have become less functionally important among Neandertals and modern humans.