A Genetic Analysis of the Gibraltar Neanderthals

The skulls from Forbes' Quarry and Devil's Tower in Gibraltar are among the first Neanderthal remains ever found. Here, we show that small amounts of ancient DNA are preserved in the petrous bones of the two individuals in spite of unfavorable climatic conditions. However, the endogenous Neanderthal DNA is present among an overwhelming excess of recent human DNA. Using improved DNA library construction methods that enrich for DNA fragments carrying deaminated cytosine residues, we were able to sequence 70 and 0.4 Mbp nuclear DNA of the Forbes' Quarry and Devil's Tower specimens, respectively, as well as large parts of the mitochondrial genome of the Forbes' Quarry individual. We confirm that the Forbes' Quarry individual was a female and the Devil's Tower individual a male. We also show that the Forbes' Quarry individual is genetically more similar to the ~120,000 year-old Neanderthals from Scladina Cave in Belgium and Hohlenstein Stadel in Germany and to the ~60,000-70,000 year-old Neanderthal from Russia (Mezmaiskaya 1) than to a ~49,000 year-old Neanderthal from El Sidrón in northern Spain and other younger Neanderthals from Europe and Western Asia. This suggests that the Forbes' Quarry remains predate the latter Neanderthals. The preservation of archaic human DNA in the warm coastal climate of Gibraltar, close to the shores of Africa, raises hopes for the future recovery of archaic human DNA from regions where climatic conditions are less than optimal for DNA preservation.