We may have been overlooking a surprisingly rich source of ancient DNA.
Scientists have successfully reconstructed the mitochondrial genome of the extinct wooly rhinoceros (Coelodonta antiquitatis) using DNA obtained from fossilized feces of cave hyenas (Crocuta crocuta spelea) that had consumed the rhinoceros.
This discovery marks the first recovery of a genome from wooly rhinos in Europe, as previous genomic data on the species had only come from Siberian animals. By studying this ancient DNA, we can potentially gain insights into regional variations among rhino herds and establish the significance of coprolites (fossilized feces) as a valuable resource.
“The mitochondrial genome assemblies presented in this study represent the initial records of European wooly rhinoceros and serve as a crucial resource for understanding the phylogeography of this iconic Pleistocene megafauna species,” state the researchers in their paper.
What makes this finding even more remarkable is that the rhino DNA was retrieved quite effortlessly from the coprolite of another species (without directly associated remains of the wooly rhinoceros), highlighting the importance of obtaining genomic data from diverse sources.
Interestingly, coprolites are proving to be a treasure trove of historical information. By analyzing preserved feces, researchers can decipher the diets of both humans and animals from ancient times, study the parasites they carried, and even explore changes in the human gut microbiome.
A team led by molecular biologist Peter Andreas Seeber from the University of Konstanz in Germany examined two fossilized hyena feces dating back to the Middle Paleolithic period in what is now Germany (a time span of roughly 300,000 to 30,000 years ago).
These coprolites were already excavated and stored in museum collections, similar to many other coprolites. A study published last year has emphasized the underestimated significance of coprolites in museum collections for studying the biological history of our planet.
Seeber and his team employed specialized techniques to extract DNA material from within the coprolites, prepared it for sequencing, and ran the samples through a DNA sequencer.
Although the DNA was degraded, the researchers managed to recover genetic material from both the cave hyena and the wooly rhino, allowing them to compare the genomes with those of modern and ancient samples.
Despite the rhino DNA originating from a singular sample, it revealed novel insights into the species and its evolution across Eurasia.
Interestingly, the differences observed between the European rhino consumed by hyenas and the Siberian rhinos suggest that these two groups began diversifying a considerable time ago. The divergence of the European rhino population occurred between 2.5 million and 150,000 years ago.
This finding challenges the hypothesis that rhinos repeatedly expanded their range into Western Europe during the late Pleistocene period, at least in the case of this particular group.
Further retrieval and analysis of genetic material from these ancient and majestic rhinos will provide more insights into their history, even if it means extracting DNA from something as unglamorous as feces.
“Similar to these samples, many archaeological objects obtained in past excavations and stored in collections remain an untapped source of ancient DNA,” note the researchers.
The study has been published in Biology Letters.
