On Dec. 10, 2024, researchers reported that DNA recovered from ancient remains is transforming our understanding of organisms and ecosystems from tens, thousands and even millions of years ago – but the growing volume of data must be better preserved.

Most DNA sequence data are now archived in dedicated, publicly accessible databases, and the ancient DNA field has been heralded by some as a poster child for best practices in genetic data sharing. However, as the pace of ancient DNA research has increased — largely thanks to the latest capabilities in DNA sequencing — so, too, have problems with data archiving. Ancient genomic data have been obtained from more than 10,000 humans, some 700 microbes and viruses and, by our estimate, more than 2,000 plant and non-human animal samples. At least 2,200 ancient host-associated and environmental microbiomes (communities of microorganisms) have been sequenced. One major problem, however, is that not all sequences end up being archived.

In about half of the papers, researchers archived only those sequences that they had managed to align to a reference genome, such as that for ancient human remains, leaving no record of the unaligned sequences. This represents a permanent loss of data for more than 3,000 ancient samples analysed in just these studies. Several initiatives are under way to recover metadata for published ancient genomic data and systematically package them into more user-friendly resources