Scientists have found the oldest parasite DNA ever recorded in the faeces of a pre-historic puma that roamed Argentina’s mountains thousands of years ago.
A team of Argentinian scientists from the National Council of Scientific and Technical Research (CONICET) made the discovery after studying a coprolite taken from a rock-shelter in the Catamarca Province.
Radiocarbon dating revealed that the parasitic roundworm eggs preserved inside the coprolite dated back to between 16,570 and 17,000 years ago, as the last Ice Age was drawing to an end.
The discovery represents the oldest record of an ancient DNA sequence for a gastrointestinal nematode parasite of wild mammals, the oldest molecular parasite record worldwide, and a new maximum age for the recovery of old DNA of this origin, according to Science Daily.
Due to weather conditions prevalent back then, the area around the shelter at Peñas de las Trampas in the southern Andean Puna is believed to have been a suitable habitat for megafauna like giant ground sloths, and also smaller herbivores like American horses and South American camelids which the pumas may have preyed on.
The study, published in the journal Parasitology, explains that the extremely dry, cold and salty conditions would have played a role in reducing the breakdown of the DNA and allowing it to be preserved.
Using ancient mitochondrial DNA analysis, the scientists were able to confirm that the coprolite came from a Puma (Puma concolor) and that the eggs belonged to Toxascaris leonina, a species of roundworm still commonly found in the digestive systems of modern day cats, dogs and foxes.
Led by Romina Petrigh and Martín Fugassa, the study was carried out by an interdisciplinary team including archaeologists and biologists as part of a project that considers ancient faeces as important paleobiological reservoirs.
Dr Petrigh, from the National University of Mar del Plata and CONICET, said, "While we have found evidence of parasites in coprolites before, those remains were much more recent, dating back only a few thousand years. The latest find shows that these roundworms were infecting the fauna of South America before the arrival of the first humans in the area around 11,000 years ago."
She added, "I was very happy when I discovered how old this DNA was. It's difficult to recover DNA of such an old age as it usually suffers damage over time. Our working conditions had to be extremely controlled to avoid contamination with modern DNA, so we used special decontaminated reagents and disposable supplies. Several experiments were performed to authenticate the DNA sequences obtained and the efforts of the team of researchers who participated was essential."