Mythbusting thriller science: Jurassic Park #2

This series of Science Thriller Mythbusting tackles the most famous of all thriller science myths, the cloning of dinosaurs using DNA extracted from insects preserved in amber.

Part 2:

The question now becomes, what happens to the dino DNA inside the gut of an insect?

Recent research published in forensics journals demonstrates the feasibility of extracting DNA from maggots and other insects and using that DNA to identify the person on whom the insect had fed.  Therefore, it’s possible for DNA to survive the degrading enzymes of the gut enough to extract sequence.

But how much sequence, and of what quality?

With today’s sequencing technology (which vastly exceeds what existed when Crichton wrote his books), virtually a single copy of the DNA is enough to amplify and sequence.  But finding enough sequence to make an identity match with a victim is many orders of magnitude simpler than sequencing an entire unknown genome from scratch.  At the least, the DNA will have gaps (more on that in next post).

Contamination is a huge problem with any type of DNA analysis that involves amplification of a tiny amount of starting material.  Deciding whether a particular sequence came from a T. rex or a pteradactyl would be very difficult without something to compare it to.  Not to mention the obvious problem of an overwhelming amount of the insect’s own DNA.

Finally, even if enough DNA was preserved intact in the insect fossil, what is the half-life of DNA due to natural decay?

One estimate published in Nature in 2007 uses microbial samples from Antarctic ice to estimate a half-life of 1.1 million years.  The authors attribute DNA decay to exposure to cosmic rays.  This is a very rough estimate to begin with, and it also suggests that the true rate of decay of DNA will depend heavily on well-protected it is.  (Dinosaurs lived on the order of hundreds of millions of years ago; the Jurassic era was from about 150-200 MYA.)

Amber is a very good preservative.  It is possible that some dinosaur DNA would have survived to the present.

But it wouldn’t be intact.  See post #3 for more!

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