Betty Bee - 03:08 The wildest dreams of many palaeontologists and recreational dino-philes were crushed this week when a study from The University of Manchester killed the Jurassic Park theory of recreating dinosaurs from elegantly extracted dino DNA released from amber-entombed mosquitos. The paper, published this week in PLoS ONE, attempted to identify the ancient DNA (aDNA) of bees preserved in copal, a precursor of amber. According to first author Dr David Penney, an amber expert, he and the rest of the group lead by Professor Terry Brown, an aDNA expert, have shown that though, “Intuitively, one might imagine that the complete and rapid engulfment in resin, resulting in almost instantaneous demise, might promote the preservation of DNA in a resin entombed insect, … this appears not to be the case”. For many years it appeared the extraction of aDNA from fossils trapped in amber was a reality, as several studies from the early 1990s to today have purported to recover aDNA from mostly bacterial species, and a few insects and plants. These studies were primarily based on identification of aDNA through polymerase chain reaction (PCR). PCR is the process of synthesising more DNA from existing DNA. In this technique, the DNA is not directly extracted from the sample and sequenced, but instead the quantity of DNA is increased through successive rounds of synthesis and then the amplified bits are sequenced. Unfortunately, PCR will preferentially amplify more abundant and undamaged modern DNA over degraded aDNA. This suggests that any contamination in the sample will be overrepresented and possibly hide any true aDNA. These results effectively end the idea that amber-entrapment is effective in DNA preservation. Since aDNA was not detected in the young copal then results in even older amber stand to be the same or worse. The authors have had previous success isolating aDNA from Mycobacterium tuberculosis in human bone, as published in the Proceedings of the National Academy of Sciences, and archeological plant remains from charred cereal grains, as published in the Journal of Archaeological Science, so it is tough to disregard the most recent results. In the words of Dr Penney, “Unfortunately, the Jurassic Park scenario must remain in the realms of fiction”. plosone.org/article/info:doi/10.1371/journal.pone.0073150 siriscientificpress.co.uk/Pages/DavidPenneyresearch.aspx telegraph.co.uk/science/dinosaurs/10303795/Jurassic-Park-ruled-out-dinosaur-DNA-could-not-survive-in-amber.html
Posted on: Wed, 18 Sep 2013 11:36:06 +0000
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