by Lee Falin, PhD
Jurassic Park has become a classic of science fiction films. Many of its more iconic scenes have been parodied by other, newer films, including the Toy Story series, The Simpsons, and even Scooby Doo. In addition, the breathtaking computer animation used in the film opened the doors for filmmakers around the world to create scenes that they previously thought would be too costly or even impossible to film.
While its impact on popular culture is indisputable, unfortunately the science portrayed in the film is not as laudable as its computer graphics. Let’s look at what the film gets right and where it misses the mark.
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Mosquitos in Amber
None of the fancy dinosaurs in the film would be possible without those hardworking (and likely underpaid) amber miners. The source of “Dino DNA,” as the film refers to it, comes from the blood contained within the fossilized remains of mosquitos that have been trapped in amber. Amber is the fossilized form of resin, which is the sticky stuff you might see oozing out of pine trees. Amber is formed when resin is subjected to high pressure and temperatures for an extended period of time.
Mosquitos and other insects are commonly found in amber, probably due to the fact that plants tend to use resin as a defense against insect damage. The oldest mosquito found in amber that I could find record of, dates back to around 90 million years ago. Making it very likely that it lived around the same time as many of the dinosaurs portrayed in the film.
What’s in a Name?
Speaking of time periods, the name of the theme park (and the film) is a bit misleading. The “Jurassic” period is a span of time ranging from 145 million to around 200 million years ago. Unfortunately, with the exception of the stegosaurus and brachiosaurus (brachiosauri…brachiosaruses…?), none of the major dinosaurs portrayed in the film lived during that period.
Tyrannosaurus rex, triceratops, and the infamous velociraptor, all lived during the latter part of the cretaceous period, which occurred around 66 to 100 million years ago. I suppose “Cretaceous Park” doesn’t have as nice a ring to it. This also makes one wonder how the park scientists were able to get the DNA for the stegosaurus and brachiosaurs, since they lived tens of millions of years before the first mosquito we have record of. Hmmm…
Mosquitos and DNA
Which brings us to our next question: Can DNA from a mosquito’s last meal be sucked out of its tummy? The answer to this question is a definite yes. One of the notable things about red blood cells is that unlike almost every other cell of your body, they don’t contain any DNA. Fortunately for those wanting to create dinosaur theme parks, white blood cells do contain DNA and can be found inside mosquito blood meals.
In fact, scientists are able to use the DNA found in mosquitos for forensic analysis in solving crimes, and in epidemiological studies that involve tracking which people mosquitos have bitten.
Dino DNA
So with the minor problem of us being unable to determine whether or not mosquitos lived at the same time as a couple of the dinosaurs in the film, everything seems to be going along pretty well. Fossilized mosquitos have been found in amber, mosquito blood meals do contain DNA, and we know at least some dinosaurs lived at the same time as mosquitos. So we should be headed to Cretaceous, er Jurassic Park any day now, right?
Unfortunately, DNA tends to break down when sitting around outside of cells (a process known as degradation). Recent research has shown that DNA has a half-life of about 521 years. Meaning, that if you were to leave a sample of DNA sitting in your living room for 521 years, about half of its chemical bonds would break down.
The research also calculates that even under ideal low-temperature storage conditions, every single bond would be broken after about 6.8 million years (assuming your living room lasted that long). Higher temperatures (required to form amber) and extreme pH levels (such as found in the stomach of a mosquito) increase the rate at which DNA degrades – which unfortunately rules out the possibility of finding any intact (or even partially intact) dinosaur DNA inside the mosquito’s belly.
Conclusion
So now you know that even ignoring the feasibility of the science involved in the actual dinosaur cloning, we’ve run into several roadblocks on the road to Jurassic Park. Not the least of which is the fact that while DNA samples can be found in mosquitos, they wouldn’t have lasted long enough to allow us to find dinosaur DNA in the 1990s.
