Recovery and amplification of ancient DNA from Herculaneum victims killed by the 79 AD Vesuvius hot surges

Abstract

In thermally damaged archaeological bones the quantity, quality, and amplifiability of DNA are very much reliant on both the extent of heating and the environmental conditions of the burial context. In this study we tested the possibility of extracting and amplifying ancient DNA from human bone remains of Herculaneum victims of the 79 AD eruption of Vesuvius using a combination of histochemical and molecular methods. Long bone samples with variable degrees of chromatic and morphological alterations consistent with exposure to temperatures of about 300 °C were taken from four specimens. Using histochemical stains, bone cryostat sections from three individuals revealed DNA within osteocyte lacunae but only for one sample the DNA was suitable for PCR amplification obtained, namely from reactions with the primer pair for X and Y amelogenin (AMEL) loci. The relative sequence differed from the homologous trait of AMELX deposited in GenBank for six bases, probably due to degradation processes following death. Our data are indicative that archaeological bones exposed to high temperatures of about 300 °C should be considered for DNA analysis, given the favorable conditions of corpse burial and skeleton preservation, such as those that occurred for the 79 AD victims in Herculaneum and Pompeii.

Molecular signatures written in bone proteins of 79 AD victims from Herculaneum and Pompeii

“…At Herculaneum, instead, after the rapid vanishing of soft tissue by ≥ 500 °C exposure 22 , the permanently waterlogged ash bed in which the skeleton was buried must have inhibited the microbial chemical modifications, allowing the long-term survival of organic matter. Such a type of environmental context seems to explain the reason of the highlighted good preservation of proteins, as well as the survival of collagen and DNA 24 , 87 .…”

Bioarchaeological and palaeogenomic portrait of two Pompeians that died during the eruption of Vesuvius in 79 AD

“…6 These authors contributed equally: Olga Rickards and Fabio Macciardi. * email: gabrielescor@gmail.com; pierfrancesco.fabbri@unisalento.it; fmacciar@uci.edu Past studies have shown the possibility of retrieving genetic data from both human and zooarchaeological remains in Pompeii [6][7][8][9][10][11][12] , but those initial analyses were limited to short stretches of mitochondrial DNA obtained using PCR-based methods. New available methodologies, based on high-throughput shotgun sequencing, DNA capture, enrichment strategy 13,14 , as well as using optimal sources of ancient DNA (aDNA) from teeth and petrous bones 15,16 , have dramatically increased the amount of data that can be obtained from previously unsuitable samples for genetic research, and may open new avenues to substantially increase the knowledge of the genetic diversity in the ancient Pompeian population.…”