TY - JOUR

T1 - Evidence of authentic DNA from Danish Viking Age skeletons untouched by humans for 1,000 years

AU - Melchior, Linea

AU - Kivisild, Toomas

AU - Lynnerup, Niels

AU - Dissing, Jørgen

N1 - Keywords: Archaeology; Base Sequence; Bone and Bones; DNA, Mitochondrial; Denmark; Fossils; Haplotypes; Humans; Molecular Sequence Data; Polymerase Chain Reaction; Sequence Homology, Amino Acid

PY - 2008

Y1 - 2008

N2 - BACKGROUND: Given the relative abundance of modern human DNA and the inherent impossibility for incontestable proof of authenticity, results obtained on ancient human DNA have often been questioned. The widely accepted rules regarding ancient DNA work mainly affect laboratory procedures, however, pre-laboratory contamination occurring during excavation and archaeological-/anthropological handling of human remains as well as rapid degradation of authentic DNA after excavation are major obstacles. METHODOLOGY/PRINCIPAL FINDINGS: We avoided some of these obstacles by analyzing DNA from ten Viking Age subjects that at the time of sampling were untouched by humans for 1,000 years. We removed teeth from the subjects prior to handling by archaeologists and anthropologists using protective equipment. An additional tooth was removed after standard archaeological and anthropological handling. All pre-PCR work was carried out in a "clean- laboratory" dedicated solely to ancient DNA work. Mitochondrial DNA was extracted and overlapping fragments spanning the HVR-1 region as well as diagnostic sites in the coding region were PCR amplified, cloned and sequenced. Consistent results were obtained with the "unhandled" teeth and there was no indication of contamination, while the latter was the case with half of the "handled" teeth. The results allowed the unequivocal assignment of a specific haplotype to each of the subjects, all haplotypes being compatible in their character states with a phylogenetic tree drawn from present day European populations. Several of the haplotypes are either infrequent or have not been observed in modern Scandinavians. The observation of haplogroup I in the present study (<2% in modern Scandinavians) supports our previous findings of a pronounced frequency of this haplogroup in Viking and Iron Age Danes. CONCLUSION: The present work provides further evidence that retrieval of ancient human DNA is a possible task provided adequate precautions are taken and well-considered sampling is applied.

AB - BACKGROUND: Given the relative abundance of modern human DNA and the inherent impossibility for incontestable proof of authenticity, results obtained on ancient human DNA have often been questioned. The widely accepted rules regarding ancient DNA work mainly affect laboratory procedures, however, pre-laboratory contamination occurring during excavation and archaeological-/anthropological handling of human remains as well as rapid degradation of authentic DNA after excavation are major obstacles. METHODOLOGY/PRINCIPAL FINDINGS: We avoided some of these obstacles by analyzing DNA from ten Viking Age subjects that at the time of sampling were untouched by humans for 1,000 years. We removed teeth from the subjects prior to handling by archaeologists and anthropologists using protective equipment. An additional tooth was removed after standard archaeological and anthropological handling. All pre-PCR work was carried out in a "clean- laboratory" dedicated solely to ancient DNA work. Mitochondrial DNA was extracted and overlapping fragments spanning the HVR-1 region as well as diagnostic sites in the coding region were PCR amplified, cloned and sequenced. Consistent results were obtained with the "unhandled" teeth and there was no indication of contamination, while the latter was the case with half of the "handled" teeth. The results allowed the unequivocal assignment of a specific haplotype to each of the subjects, all haplotypes being compatible in their character states with a phylogenetic tree drawn from present day European populations. Several of the haplotypes are either infrequent or have not been observed in modern Scandinavians. The observation of haplogroup I in the present study (<2% in modern Scandinavians) supports our previous findings of a pronounced frequency of this haplogroup in Viking and Iron Age Danes. CONCLUSION: The present work provides further evidence that retrieval of ancient human DNA is a possible task provided adequate precautions are taken and well-considered sampling is applied.

U2 - 10.1371/journal.pone.0002214

DO - 10.1371/journal.pone.0002214

M3 - Journal article

C2 - 18509537

VL - 3

SP - e2214

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 5

ER -