Jurassic Park… the first thing most people think of when they hear the term ‘ancient DNA’. Millions-of-year-old dinosaur DNA from mosquitoes preserved in amber can be used to recreate dinosaurs in the modern world, right? Well, not quite. Exciting times certainly followed the first reported discovery of ancient DNA (aDNA) in the mid-1980s: anything seemed possible, including recreating extinct species – as illustrated with great effect by a certain Spielberg-directed film.
But by the early 1990s, sobering evidence was emerging that contamination of ancient material with modern DNA was a major (and possibly insurmountable) problem. The miniscule amount of aDNA preserved in ancient material – and the nature of the amplification techniques applied in order to obtain an identifiable DNA sequence – meant that even the most unimaginably tiny contamination could lead to wildly erroneous results. Claims of millions-of-year-old DNA suddenly didn’t seem so reliable. Scientists questioned whether laboratory techniques could ever advance to the stage that contamination could be entirely ruled out. But over the last decade and a half or so, rigorous technical procedures to limit contamination, along with new sequencing techniques, have led to exciting times for aDNA research once again.
Although it’s unlikely that we’ll be repopulating the planet with dinosaurs anytime soon (the oldest aDNA successfully extracted and identified is from a 700,000-year-old horse, long after the extinction of the dinosaurs 65 million years ago), luckily there is no need to despair: aDNA has many possible uses beyond recreating dinosaurs. One such use is discussed in an upcoming paper in the journal Conservation Biology (co-authored by Gayle McGlynn from Geography).
The paper assesses the use of aDNA as a source of potential information for conservation management. Global climate change is widely seen as a threat to the world’s mountain regions – particularly in the tropics, which contain mountain regions of exceptionally high biodiversity. Conservation of future biodiversity may increasingly depend upon the availability of scientific information to set suitable restoration targets that represent ‘pre-human impact conditions’ – but where do we get this scientific information from? ‘Traditional’ sources of evidence include using pollen analysis to reconstruct past vegetation, but there are limits to the level of detail available from pollen data from high-altitude tropical sites.
By comparing the results of sediment aDNA and pollen analysis from the same sediment cores, we could evaluate the different information provided by these two very different methods. Our results indicate that sediment aDNA results complement pollen data in reconstructing past high-altitude vegetation, and particularly with regard to assessing vegetation change at different geographic scales. This could help to provide important information on restoration targets and the nature and magnitude of human-induced environmental changes in high conservation priority, biodiversity hotspots. So aDNA can be a very useful tool in the most unexpected of circumstances – even if we’re probably not facing a Jurassic Park-type situation anytime soon.
For more information on the location see our previous post ‘As clear as mud‘