| |
 |
|
|
Science Forum Index » Anthropology - Paleo Forum » Paper: Evidence of Authentic DNA from Danish Viking...
Page 1 of 1
|
| Author |
Message |
| Robert Karl Stonjek... |
 Posted: Thu May 29, 2008 12:38 am |
|
|
|
Guest
|
Evidence of Authentic DNA from Danish Viking Age Skeletons Untouched by Humans for 1,000 Years
Linea Melchior1, Toomas Kivisild2, Niels Lynnerup3, Jørgen Dissing1
1 Research Laboratory, Institute of Forensic Medicine, University of Copenhagen, Copenhagen, Denmark
2 Leverhulme Center for Human Evolutionary Studies, The Henry Wellcome Building, University of Cambridge, Cambridge, United Kingdom
3 Laboratory of Biological Anthropology, Institute of Forensic Medicine, University of Copenhagen, Copenhagen, Denmark
Abstract
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.
Citation: Melchior L, Kivisild T, Lynnerup N, Dissing J (2008) Evidence of Authentic DNA from Danish Viking Age Skeletons Untouched by Humans for 1,000 Years. PLoS ONE 3(5): e2214. doi:10.1371/journal.pone.0002214
Editor: Niyaz Ahmed, Centre for DNA Fingerprinting and Diagnostics, India
Received: February 7, 2008; Accepted: April 2, 2008; Published: May 28, 2008
Copyright: © 2008 Melchior et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by external funding from the VELUX FOUNDATION. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: joergen.dissing at (no spam) forensic.ku.dk
Introduction
Early attempts to retrieve DNA from ancient sources involved molecular cloning [1]-[3], however, with the invention of the PCR technique [4] sensitivity was dramatically improved and soon a sense that "everything" was possible led to numerous reports on DNA sequences from species thousands or even millions of years old (for review see [5]). Eventually it became clear that many of these early results were in fact due to contaminating modern DNA. This was especially true for results on ancient humans because of the abundance of modern human DNA [5]-[7]. In the past few years several studies have taken previous mistakes into account and it has been shown that when strict measures are observed, the recovery of authentic ancient human DNA may be possible [8]-[16]. Recently researchers have pointed out that the generally accepted laboratory "rules" (see e.g. [17]), which are well suited to avoid or account for laboratory derived contamination, may not be sufficient to detect more worrisome contamination added to the material during excavation and subsequent handling (pre-laboratory contamination) [18]-[20]. Furthermore, Sampietro at al. 2006 [19] showed that modern contaminating sequences after about 10 years of storage may show the same amount of damage as is seen in ancient DNA (aDNA), so that "damage patterns" no longer can be argued as an authentication criterion.
We are currently analyzing aDNA from human remains from the Danish and Greenland past to shed light on population heterogeneity, population affinity and family relationships. We have obtained mitochondrial DNA (mtDNA) sequence results on subjects from an early Christian cemetery (AD 1,000-1,250), two Roman Iron Age settlements (AD 0-400) and from Greenland Inuit (AD ~1,450) 14, 16, 21. In the present work we had the opportunity to obtain samples for aDNA analysis from ten Viking Age [22] subjects that at the time of sampling were untouched by humans for 1,000 years.
Source: PLoS [Open Access]
http://www.plosone.org:/article/info:doi/10.1371/journal.pone.0002214
--
Posted by
Robert Karl Stonjek |
|
|
| Back to top |
|
| |
|
Page 1 of 1
All times are GMT - 5 Hours
The time now is Sun Oct 12, 2008 4:57 pm
|
|