How living history is being written into rocks | Fossils

Fossilisation is rare. Most living things disappear without trace, recycled back into planet Earth.But in some environments the DNA from living things binds to the soil and rock, leaving a marker of their existence for hundreds of thousands or even millions of years.Now scientists are using DNA from sediments (sedaDNA) to reconstruct a far clearer picture of past environments, for example using it to show that woolly mammoths lived in the Arctic long after they were thought to be extinct from the region, or tracing the history of soft-bodied creatures that do not normally fossilise, such as worms.Every living thing leaves traces of their DNA – in flakes of skin, hair, faeces, urine, pollen or decaying tissue – everywhere they go.Writing in Geoscientist, Tony Brown from the University of Southampton explains how, under the right circumstances, that DNA can be incorporated into a mineral structure and preserved.In Norway, researchers have been able to match sedaDNA with ancient rock paintings of animals on cave walls.Meanwhile, Brown and his colleagues are working on a project known as PortGEN, sifting through the sedaDNA in sediments from ancient world ports including Rome and Venice to gain new insights into the lives of ancient civilisations.The possibilities of sedaDNA are immense: it is one to watch.