Some of the bacterium's genes appear to be inherited from a related species. Others have been found in archaea, a group of organisms evolutionarily distinct from bacteria. Chivian says D. audaxviator may have evolved as it travelled down through the cracks in the rock, and acquired archaea genes through horizontal gene transfer from populations it crossed on its way down.
"It can't handle oxygen," he says. This suggests it has not been exposed to pure oxygen for a long time. The water in which D. audaxviator lives has not seen the light of day in over 3 million years, and this could be an indication of how old the species is.
In fact, the species got its name from its long journey towards the centre of the Earth. In Jules Verne's novel by that name, the fictional Professor Lindenbrock's journey is triggered by the following message in Latin: "descende, Audax viator, et terrestre centrum attinges" – meaning "descend, bold traveller, and attain the center of the Earth".