A new and rapid method for analysing single unidentified fragments within bulk bone samples via ancient DNA (aDNA) sequencing is described in the journal Scientific Reports this week. Small fragments of bone are commonly found in archaeological and palaeontological digs but can be difficult to identify, and aDNA analysis of single samples can be costly and time-consuming.
Michael Bunce and colleagues present a ‘bulk-bone’ approach whereby they extracted and amplified aDNA dating as far back as about 46,000 years ago from blended samples of bone powder. Each sample contained material from 50?150 fossil fragments found within one of 15 sediment layers across two archaeologically significant sites in Australia: Devil’s Lair and Tunnel Cave. They screened the extracted aDNA for amplifiable mitochondrial DNA, which was then sequenced using high-throughput sequencing (a metabarcoding approach). The authors then performed a taxonomic analysis, which indicated that the samples contained DNA from a range of mammals, birds and reptiles.
The rapid and cost-effective analysis of bulk bone samples from excavations and test pits without damaging morphologically important samples represents a valuable tool for archaeologists and palaeontologists. These results offer an initial demonstration of a technique that shows promise for such analysis, and may potentially help to uncover information about past biodiversity from samples that could have otherwise been discarded. However, further work is required to reliably infer information about genetic diversity over time and improve taxonomic identification to the species level.