Article

Assessing the fidelity of ancient DNA sequences amplified from nuclear genes.

Ancient DNA and Evolution Group, Centre for Ancient Genetics, Niels Bohr Institute, University of Copenhagen, Denmark.
Genetics (Impact Factor: 4.39). 02/2006; 172(2):733-41. DOI: 10.1534/genetics.105.049718
Source: PubMed

ABSTRACT To date, the field of ancient DNA has relied almost exclusively on mitochondrial DNA (mtDNA) sequences. However, a number of recent studies have reported the successful recovery of ancient nuclear DNA (nuDNA) sequences, thereby allowing the characterization of genetic loci directly involved in phenotypic traits of extinct taxa. It is well documented that postmortem damage in ancient mtDNA can lead to the generation of artifactual sequences. However, as yet no one has thoroughly investigated the damage spectrum in ancient nuDNA. By comparing clone sequences from 23 fossil specimens, recovered from environments ranging from permafrost to desert, we demonstrate the presence of miscoding lesion damage in both the mtDNA and nuDNA, resulting in insertion of erroneous bases during amplification. Interestingly, no significant differences in the frequency of miscoding lesion damage are recorded between mtDNA and nuDNA despite great differences in cellular copy numbers. For both mtDNA and nuDNA, we find significant positive correlations between total sequence heterogeneity and the rates of type 1 transitions (adenine --> guanine and thymine --> cytosine) and type 2 transitions (cytosine --> thymine and guanine --> adenine), respectively. Type 2 transitions are by far the most dominant and increase relative to those of type 1 with damage load. The results suggest that the deamination of cytosine (and 5-methyl cytosine) to uracil (and thymine) is the main cause of miscoding lesions in both ancient mtDNA and nuDNA sequences. We argue that the problems presented by postmortem damage, as well as problems with contamination from exogenous sources of conserved nuclear genes, allelic variation, and the reliance on single nucleotide polymorphisms, call for great caution in studies relying on ancient nuDNA sequences.

0 Bookmarks
 · 
152 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A fundamental need in conserving species and their habitats is defining distinct entities that range from individuals to species to ecosystems and beyond (Table 1; Ryder 1986, Moritz 1994, Mayden and Wood 1995, Haig and Avise 1996, Hazevoet 1996, Palumbi and Cipriano 1998, Hebert et al. 2004, Mace 2004, Wheeler et al. 2004, Armstrong and Ball 2005, Baker 2008, Ellis et al. 2010, Winker and Haig 2010). Rapid progression in this interdisciplinary field continues at an exponential rate; thus, periodic updates on theory, techniques, and applications are important for informing practitioners and consumers of genetic information. Here, we outline conservation topics for which genetic information can be helpful, provide examples of where genetic techniques have been used best in avian conservation, and point to current technical bottlenecks that prevent better use of genomics to resolve conservation issues related to birds. We hope this review will provide geneticists and avian ecologists with a mutually beneficial dialogue on how this integrated field can solve current and future problems.
    The Auk 01/2011; 128:205-229. · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: One of the major problems in ancient DNA work is the presence of inhibitory substances, which hampers Taq polymerase activity. Therefore analysis of ancient DNA sample is very challenging. Here we describe a simple and competent ethanol re-precipitation based protocol for the purification of DNA from ancient bones and tissues. The efficiency of this procedure has been demonstrated on 600 years old biological samples provided by Anthropological Survey of India (Himalaya region). This suggests that re-precipitation of ancient DNA extracts removes PCR inhibitors and increases the success rate of amplification.
    Antrocom Online Journal of Anthropology ISSN 1973-2870. 01/2011;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: DNA preserved in degraded beetle (Coleoptera) specimens, including those derived from dry-stored museum and ancient permafrost-preserved environments, could provide a valuable resource for researchers interested in species and population histories over timescales from decades to millenia. However, the potential of these samples as genetic resources is currently unassessed. Here, using Sanger and Illumina shotgun sequence data, we explored DNA preservation in specimens of the ground beetle Amara alpina, from both museum and ancient environments. Nearly all museum specimens had amplifiable DNA, with the maximum amplifiable fragment length decreasing with age. Amplification of DNA was only possible in 45% of ancient specimens. Preserved mitochondrial DNA fragments were significantly longer than those of nuclear DNA in both museum and ancient specimens. Metagenomic characterisation of extracted DNA demonstrated that parasite-derived sequences, including Wolbachia and Spiroplasma, are recoverable from museum beetle specimens. Ancient DNA extracts contained beetle DNA in amounts comparable to museum specimens. Overall, our data demonstrate that there is great potential for both museum and ancient specimens of beetles in future genetic studies, and we see no reason why this would not be the case for other orders of insect. This article is protected by copyright. All rights reserved.
    Molecular Ecology Resources 05/2014; 14(3):606-615. · 7.43 Impact Factor

Full-text

Download
63 Downloads
Available from
Jun 5, 2014