Biology subjects

Dittmar, J. M.

Publications and source records attributed to Dittmar, J. M..

3 recordsLinked to original sources

bioRxiv2024

Bone adhered soil as a source of target and environmental DNA and proteins

In recent years, sediments from cave environments have provided invaluable insights into ancient hominids, as well as past fauna and flora. Unfortunately, locations with favourable conditions for ancient DNA (aDNA) preservation in sediments are scarce. In this study we analysed a set of samples obtained from soil adhered to different human skeletal elements, originating from Neolithic to Medieval sites in England, and performed metagenomics and metaproteomics analysis. From them, we were able to recover aDNA sequences matching the genomes of endogenous gut and oral microbiome bacteria. We also found the presence of genetic data corresponding to animals and plants. In particular we managed to retrieve the partial genome and proteome of a Black Rat (Rattus rattus), sharing close genetic affinities to other medieval Rattus rattus. Furthermore, we have also been able to reconstruct a partial human genome. The genetic profile of those human sequences matches the one recovered from the original skeletal element. Our results demonstrate that material usually discarded, as it is soil adhering to human remains, can be used to get a glimpse of the environmental conditions at the time of the death of an individual, even in contexts where due to harsh environmental conditions, the skeletal remains themselves are not preserved.

genomics↗

bioRxiv2024

2500 Years of Human Betaherpesvirus 6A and 6B Evolution Revealed by Ancient DNA

Human betaherpesviruses 6A and 6B are double-stranded DNA viruses, specialised in infecting humans and are best known as the main causative pathogens of the common childhood infection "sixth disease". Despite only being discovered in the 1980s, these viruses are speculated to have a much longer and more complex history within the human population than available modern data make clear. The viruses are carried by large fractions of the human population and can integrate into the human genome, leading to a wide range of clinical manifestations of varied severity. Here, we present the first nine full and two partial ancient genomes of HHV-6A and 6B, dating as far back as the Italian Iron Age (ca. 1100-600 BCE). We demonstrate that large fractions of the current HHV-6 diversity were already well established in the human population by the 14th century CE. Our data suggests that HHV-6B integrated into the human genome at the latest before the 1st-6th century CE, with two integrated clades being populated by ancient DNA genomes in our phylogeny, which further supports that they originated from likely much older ancient founder events. Additionally, we show that all known inherited chromosomally integrated (ici-)HHV-6A clades were already represented in European historical populations, confirming that ici-HHV-6A no longer integrates into the human germline within populations of European ancestry and likely endogenized in early human history. Finally, our results demonstrate the unique suitability of archaeological remains and ancient DNA for the study of the evolution of integrated viruses in human populations.

evolutionary biology↗

bioRxiv2022

Ancient herpes simplex 1 genomes reveal recent viral structure in Eurasia

Human herpes simplex virus 1 (HSV-1), a life-long infection spread by oral contact, today infects a majority of adults globally1, yet no ancient HSV-1 genomes have yet been published. Phylogeographic clustering of sampled diversity into European, pan-Eurasian, and African groups2, 3 has suggested that the virus co-diverged with anatomically modern humans migrating out of Africa4, although a much younger origin has also been proposed5. The lack of ancient HSV-1 genomes, high rates of recombination, and high mobility of humans in the modern era have impeded the understanding of HSV-1s evolutionary history. Here we present three full ancient European HSV-1 genomes and one partial genome, dating to between the 3rd and 17th century CE, sequenced to up to 9.5x with paired human genomes up to 10.16x. These HSV-1 strains fall within modern Eurasian diversity. We estimate a mean mutation rate of 7.6 x 10-7 - 1.13 x 10-6 for non-African diversity leading to an estimated age of sampled modern Eurasian diversity to 4.68 (3.87 - 5.65) kya. Extrapolation of these rates indicate the age of sampled HSV-1 to 5.29 (4.60-6.12 kya, suggesting lineage replacement coinciding with late Neolithisation and implicating Bronze Age migrations6 in the distribution of HSV-1 through Eurasia.

genomics↗