An Austrian-American research team (University of Vienna, Department Evolutionary Anthropology and Harvard Medical School, Department of Genetics), in collaboration of Hungarian experts from Eötvös Loránd University, has developed a new method that allows the almost non-destructive extraction of genetic material from archaeological human remains. The method allows anthropologists, archaeologists, and archaeogeneticists to avoid the risk of serious damage to artefacts of significant scientific and heritage value, which can then be fully examined in future research.
Bioarcheological research on human and animal remains from archaeological excavations has become increasingly important in recent decades. Both nationally and internationally, in addition to classical archaeological and anthropological research, a significant number of molecular biological way of examination are included. One of the most important fields is archaeogenetics. The study of ancient human and animal genetic material can significantly help both the analysis of human evolution and the answering of historical questions about the populations of later archaeological periods.
The first archaic DNA (aDNA) research started in the 1980s, but the real methodological breakthroughs came after the turn of the millennium. This was the period when next-generation sequencing methods reached bioarcheological research. Thanks to the large-scale research that began at that time, we now know more than 60 percent of the DNA of Neanderthals preserved in the nuclei of cells. A new human species was described on the basis of the genetic material extracted from teeth and finger bones found in Siberia, and it was recognized that, contrary to previous ideas, Neanderthal and modern Homo sapiens interbred with each other, leaving significant genetic traces in modern human groups north of the Sahara.
However, these samples for archaeogenetic analyses may involve a high degree of destruction and may therefore be of concern from a heritage conservation perspective, preventing or making it difficult to obtain and carry out the sampling.
An international team of researchers (Ron Pinhasi's laboratory at the University of Vienna and David Reich's laboratory at Harvard) has recognized this problem and has recently developed several new sampling methods to minimize the bone damage associated with sampling. Firstly, the methodological basis for drilling into the inner ear from the cranial base was developed and later it was shown that the use of auditory ossicles can significantly reduce the damage in the fining during sampling.
The latest research, published in the journal Genome Research, was carried out by the above-mentioned international team and the researchers of the Department of Anthropology (Tamás Hajdu, Krisztián Kiss, Tamás Szeniczey) and the Institute of Archaeology (Alexandra Anders, Pál Raczky) at Eötvös Loránd University.
"The new method significantly reduces the extent of damage of the findings. It consists of dissolving the DNA content of the root fragment of the tooth, rich in cellular cementum, by immersing it in a special solution. The quality of the sample thus obtained is not as good as that of DNA extracted from the inner ear, but it is of the same quality as that of the genetic material obtained by traditional methods (drilling and pulverization of the tooth). The main advantage of the method is that the tooth undergoes only to minimal damage, leaving its structure intact not only morphologically but also histologically, while its unchanged chemical composition allows subsequent isotopic tests (strontium or C14) to be carried out. The only noticeable change is the fading or whitening of the root color," said Tamas Hajdu, head of the Hungarian research group and assistant professor at the Department of Anthropology at Eötvös Loránd University.
The significance of the new sampling method, therefore, lies in its minimal destructive effect. If the sampled teeth are left intact, they can be subjected to further morphological, radiological, histological, oral pathological, stable isotope, and radiocarbon studies. This may be particularly important in cases where only a few teeth remain have been preserved from a given period and place, which may be tens of thousands of years old, and destructive sampling of these would completely preclude subsequent analysis. In addition to human evolutionary research, the new methodology could also help projects on population history and disease evolution at the Department of Anthropology and the Institute of Archaeology at Eötvös Loránd University by preserving the integrity of the findings. The new sampling method, developed in international cooperation, offers a new perspective for the preservation of artefacts for national and international museum institutions, while at the same time allowing for the almost non-destructive conduct of the latest archaeogenetic analyses.
- This press release was originally published on Eötvös Loránd University's Faculty of Science website. It has been edited for style and length