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Friday, September 27, 2013

Sorry John Hammond, no dino DNA

In Jurassic Park, scientists pull dinosaur DNA out of blood-sucking insects encased in amber that is millions of years old. University of Manchester scientists, led by David Penney, show just how implausible this intriguing idea is when they failed to extract insect DNA from 10,000 year old samples.
Certain types of trees produce thick gummy resin. Over time, the resin hardens, first into a product called ‘copal’, and then into the more familiar, and far more ancient, amber. It was from 10,000 year old copal that the entomologists tried to pull DNA. They pulverized two stingless bees embedded in the copal and, using the most stringent methodology to prevent contamination (sterilizing all surfaces and wearing forensic suits), attempted to extract DNA. 

While they did get some DNA, none of it matched known stingless bee databases. The best sequence they got was a 452 nucleotide string from a bacterium. This is about half the length of an average bacterial gene. The authors are quick to defend their DNA extraction prowess, stating that they had had no trouble getting DNA from other samples. 

To be clear, the researchers were not attempting to resurrect ancient vertebrates. As entomologists, they were primarily interested in collected the genomes of extinct or rare insects. However, it’s pretty clear that our hopes of ever visiting Jurassic Park are dashed. If you can’t get insect DNA out of an insect embedded in 10,000 year old copal, you aren’t going to be able to get dinosaur DNA from the blood meal of an insect embedded in 100 million year old amber.

Penney D, Wadsworth C, Fox G, Kennedy SL, Preziosi RF, & Brown TA (2013). Absence of ancient DNA in sub-fossil insect inclusions preserved in 'anthropocene' colombian copal. PloS one, 8 (9) PMID: 24039876.

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