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SUMMARY:New DNA approaches to understanding Late-Quaternary and recent bio
 diversity changes – potential and problems - Prof Mary E. Edwards\, Depa
 rtment of Geography and Environment\, University of Southampton (UK)
DTSTART:20150219T173000Z
DTEND:20150219T183000Z
UID:TALK57132@talks.cam.ac.uk
CONTACT:Julia Gottschalk
DESCRIPTION:Major advances in the ability to sequence many DNA samples has
  led to a proliferation of Quaternary molecular studies. The Ecochange pro
 ject developed a methodology that allows DNA of vascular plants and mammal
 s to be extracted from Quaternary sediments and used as proxy data for the
  components of terrestrial ecosystems.  It  uses an approach called "metab
 arcoding": for plants\, this is based on short (10-200 BP) sequences of ch
 loroplast or nuclear DNA.  Taxonomic resolution is potentially better than
  that of pollen and matches that of macrofossils.  Furthermore\, DNA detec
 ts the presence of taxa at when biomass levels are relatively low. I will 
 illustrate the current status of DNA-based palaeoecological reconstruction
 s with a range of modern (calibration) and fossil studies from Siberian ye
 doma\, northern lake sediments (from Svalbard and Scotland) and modern tun
 dra landscapes.  Key findings are that modern soil DNA matches the taxa pr
 esent in modern vegetation with few false positives and roughly reflects b
 iomass\, that DNA in lakes does not seem to reflect pollen when there is n
 o vegetative biomass in the catchment\, that forb taxa were a surprisingly
  large component of glacial-age vegetation across unglaciated Eurasia\, an
 d that the Holocene DNA record from Svalbard shows rapid early colonizatio
 n and resilience of the flora in the face of climatic deterioration. New a
 nd stricter protocols for sequencing and bioinformatics filtering are impr
 oving the ability to determine false positives in the data\, which were li
 kely a problem in the first\, pioneering studies.
LOCATION:Thirkill Room\, Clare College
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