How living history is being written into rocks | Fossils

Petrification is rare. Most living beings disappear without a trace, returning back to planet Earth.

But in some environments, the DNA of living things binds to soil and rocks, leaving traces of their existence for hundreds of thousands or even millions of years.

Now scientists are using DNA from sediments (sedaDNA) to reconstruct a much clearer picture of past habitats, for example using it to show that woolly mammoths lived in the Arctic long after they were thought to have gone extinct in the region, or to trace the history of soft-bodied creatures that don't usually fossilize, such as worms.

Every living thing leaves traces of its DNA – in flakes of skin, hair, feces, urine, pollen or decaying tissue – wherever it goes.

Sign up for GeologistTony Brown from the University of Southampton explains how, under certain circumstances, DNA can be incorporated into a mineral structure and stored.

In Norway, researchers were able to match sedaDNA with ancient cave paintings of animals on cave walls.

Meanwhile, Brown and his colleagues are working on a project known as PortGENsifting sedaDNA from sediments from ports of the ancient world, including Rome and Venice, to gain new insights into life in ancient civilizations.

The potential for sedaDNA is huge: it's worth watching.