Ancient dirt has provided DNA samples which in turn revealed evidence of a previously unknown human species that resided in a Georgian cave over 25,000 years ago.

A few genome sequences called SAT29 and obtained from a 25,000-year-old single soil sample from the Satsurblia Cave in the Caucasus region in Georgia opened scientists’ viewpoints to a possibly unknown population that inhabited the area in the past.

The research was conducted by an international team consisting of scientists of Ron Pinhasi and Pere Gelabert, together with Susanna Sawyer from the University of Vienna in Austria, as well as Pontus Skoglund and Anders Bergstrom from the Francis Crick Institute in London in England.

The researchers used an innovative approach which enables DNA determination in environmental samples with the help of complex sequencing methods and data analysis resources.

According to the scientists, the new approach is beneficial because it does not require skeletal remains for genome sequencing.

However, they reported they never anticipated to discover a 25,000-year-old human genome from the BIII cave layer which according to them, dates back to before the Ice Age.

The Satsurblia Cave which is a karst cave, formed in Sataphlia-Tskaltubo karst massif, was inhabited by people at different times in the Paleolithic.

Until this point, the oldest sequenced genome of a human individual from the cave was 10,000 years younger than the current one.

However, the analysis of the new genetic material revealed that the SAT29 genome represents an ancient human lineage whose traces were continued in today’s West Eurasian population.

In order to confirm the results, the scientists made a comparison between the recovered genome and the genetic sequences from bone remnants from Upper Paleolithic Dzudzuana Cave located in the same area, which provided clear evidence of genetic similarity.

In addition to the identified human genome, other mammal genomes which supposedly belonged to a wolf or a bison species were also recovered from the obtained soil samples.

The scientists used these sequences to reconstruct the wolf and bison populations in the Caucasus region and upgrade the collected knowledge of the population dynamics of these species.

According to the press release, the next project of the international research team will be to collect samples of ancient fauna and humans from the Satsurblia cave in order to determine their mutual interactions.

Through the extraction of DNA from soil samples, the scientists hope to reconstruct the evolution of past ecosystems and evaluate the effect of climate change on mammal populations.