title: Non-destructive sampling of ancient insect DNA.
abstract: BACKGROUND
  A major challenge for ancient DNA (aDNA) studies on insect remains is that sampling procedures involve at least partial destruction of the specimens. A recent extraction protocol reveals the possibility of obtaining DNA from past insect remains without causing visual morphological damage. We test the applicability of this protocol on historic museum beetle specimens dating back to AD 1820 and on ancient beetle chitin remains from permafrost (permanently frozen soil) dating back more than 47,000 years. Finally, we test the possibility of obtaining ancient insect DNA directly from non-frozen sediments deposited 3280-1800 years ago -- an alternative approach that also does not involve destruction of valuable material.
  
  
  RESULTS
  The success of the methodological approaches are tested by PCR and sequencing of COI and 16S mitochondrial DNA (mtDNA) fragments of 77-204 base pairs (-bp) in size using species-specific and general insect primers.
  
  
  CONCLUSIONS
  The applied non-destructive DNA extraction method shows promising potential on insect museum specimens of historical age as far back as AD 1820, but less so on the ancient permafrost-preserved insect fossil remains tested, where DNA was obtained from samples up to ca. 26,000 years old. The non-frozen sediment DNA approach appears to have great potential for recording the former presence of insect taxa not normally preserved as macrofossils and opens new frontiers in research on ancient biodiversity.
authors.affiliation: Centre for Ancient Genetics and Environments, Natural History Museum and Institute of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Philip Francis
authors.initials: PF
authors.lastname: Thomsen
authors.forename: Scott
authors.initials: S
authors.lastname: Elias
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
authors.forename: James
authors.initials: J
authors.lastname: Haile
authors.forename: Kasper
authors.initials: K
authors.lastname: Munch
authors.forename: Svetlana
authors.initials: S
authors.lastname: Kuzmina
authors.forename: Duane G
authors.initials: DG
authors.lastname: Froese
authors.forename: Andrei
authors.initials: A
authors.lastname: Sher
authors.forename: Richard N
authors.initials: RN
authors.lastname: Holdaway
authors.forename: Eske
authors.initials: E
authors.lastname: Willerslev