April 28 (UPI) -- Scientists have found a way to identify the DNA of early human relatives, the Denisovans and Neanderthals, among ancient cave sediments. The method doesn't require the presence of human remains.
Evidence of the presence of early human relatives -- stone tools, carved bones and more -- has been found throughout Europe and Asia. But actual hominid remains are relatively rare.
The new method could help scientists conduct more comprehensive genomic analysis of early human relatives.
"We know that several components of sediments can bind DNA," Matthias Meyer, a researcher at the Max Planck Institute for Evolutionary Anthropology, said in a news release. "We therefore decided to investigate whether hominin DNA may survive in sediments at archaeological sites known to have been occupied by ancient hominins."
First, researchers identified genetic fragments of extinct mammals among sediments collected from the archaeological sites in Belgium, Croatia, France, Russia and Spain. The dirt samples ranged in age from 14,000 to 550,000 years old. Scientists found DNA belonging to woolly mammoths, the woolly rhinoceros, cave bears and cave hyenas.
Next, the archaeologists looked for hominid DNA.
"From the preliminary results, we suspected that in most of our samples, DNA from other mammals was too abundant to detect small traces of human DNA," explained Viviane Slon, a doctoral student at the Max Planck Institute in Leipzig. "We then switched strategies and started targeting specifically DNA fragments of human origin."
Their analysis -- published in the journal Science -- identified Neanderthal mitochondrial DNA among eight sediment samples and Denisovan DNA in another.
Researchers believe their novel analysis method could become a commonly used tool in future archaeological studies.