The delicate process of extracting dino-dna from amber fossils

The Feasibility of Cloning Dinosaurs

Exploring the science behind Jurassic Park, and weather biotech firms could possibly achieve such a large feat in genetic engineering. 

As far as I can remember, I've always loved dinosaurs. They were one of the many aspects of my childhood that made my imagination soar exponentially. Mainly through one major fact; there was once a time where these giants walked the Earth (and this wasn't from a fantasy, or story book). This was a hugely satisfying scientific and historical truth. At least for me it was…

But when it comes to dinosaurs, and when we think about them, there’s only one movie that springs to mind (no, not “The Land Before Time.,1988”). It is without a doubt, Spielberg’s classic “Jurassic Park (1993)”. Even as an adult now, the movie has a soft spot in my heart. Who could forget that scene where the Brachiosaurus are feeding?

Though lately whenever I bring up the fact that I'm a science student, some of the most interesting things people ask me relates to ‘eugenics’ and, whether or not the science behind Jurassic Park (as the book & movie describes it) is feasible. Often to my own disheartenment, I am left to explain to them that Crichton’s Jurassic Park would never have existed in the real world.

Deamidation of cytosine to uracil

To take an example, let’s first look at the idea of extracting dinosaur DNA from the blood of mosquitos preserved in amber.

When we eat, the proteins and genetic material in our food all go through a process known as “deamination”. This is the removal of an amine group from a molecule by separating and catalysing the nucleotides for energy. There are a number of enzymes involved in the breakdown of nucleotides, such as “nuclease”. So to put it simply, the digestive enzymes in the mosquitos would have already broken apart the DNA in the blood cells. But your chances of cloning a living, breathing dinosaur go down sharply from there.

Nevertheless, the book and film both accurately describe the DNA amplification process used in genetics, known as Polymerase Chain Reaction (PCR). However, one critical aspect that was not mentioned is that PCR is extremely sensitive to contamination. How PCR works is by splitting the double-helix molecule (particularly through heat) into two halves. DNA-polymerase (an enzyme used for replication) then goes down the two strands and links up any exposed strands with complementary nucleotides. Thus, creating two new double helix DNA molecules.

The process behind PCR. Source: Nature Education.

Repeat this a number of times and voilà, you will have enough DNA for test cloning (or for something as simple as DNA fingerprinting). But if you had any contaminant DNA you could probably understand how disastrous it would be for the PCR process. So let’s go back to the mosquito preserved in amber.

When extracting the blood of a mosquito preserved in amber, you would most definitely have mosquito DNA as well as viral and bacterial DNA from the gut of the mosquito. Even if there were no human contaminate DNA, it is almost absolutely guaranteed that you would not have enough coherent nucleotide sequences to clone a living, breathing dinosaur. The chances are that the animal would die before even hatching (or spontaneously abort as a zygote). To add to that, there has been 64.8 ± 0.9 million years of DNA to breakdown which results in impossible odds of ever achieving anything useful from an amber sample other than an interesting conversation piece.

Movie mistake or not. Scientists making typos is an accurate portrayal of modern day science. I'll give you that one, Spielbrrg.

Relating to the feasibility of the park, if they (somehow) managed to make DNA extraction of amber samples work, there’s no knowing what species of dinosaur you got. If you were looking for iconic dinosaurs for an attraction like Jurassic Park, say, a Stegosaurus (or even a Tyrannosaurus Rex) you would be wasting countless millions or billions of dollars on looking for the correct amber fossil with the right specimen.

Also, there are many ethical issues (which are breached multiple times) in Jurassic Park. Many of which, are left unaddressed. For example, as mentioned before sequencing dinosaur DNA from amber samples is a bit like playing dice. Consider that 99% of all organisms that ever came into existence through evolution have become extinct. Also consider that only a 1/4 or 1/3 of that figure is represented with the fossil record. When excavating, you may get organisms that were previously unknown at the time. You may even get other specimens other than dinosaurs (such as mammals or amphibians). Which is why sequencing nucleotides from amber samples will be like wearing a blindfold, and will ultimately result in mutant clones and failed hybrids.

But say that we ignore all the costs, the ethics, the incalculable work hours in the lab, and all of the problems presented. Say we actually reach the point of cloning embryos. Just from the contamination alone there is no telling what kind of diseases, birth defects, and mutations the animal might develop. So the chances are that these diseases would kill the embryo from very early on (if not, later in the long term).

Palaeogeneticist Morten Allentoft used the bones of extinct moa birds to calculate the half-life of DNA.

Nevertheless, the final nail on the coffin was when I came across a news article a few months ago regarding a recent study on the bones of a 500-6,000 year old Moa (an extinct flightless bird). The researchers from the University of Copenhagen and the University of Perth (Allentoft et al,. 2012*), had concluded after rigorous analysis that DNA breaks down over time (even when preserved under ideal conditions) due to its half life for genes of around 521 years. This was understood after drilling into the bones of 158 different Moa bones within a 5km radius at an average burial temperature of 13°C. These similar preservation conditions were key to ensuring the reliable figures for DNA decomposition, which also averaged to a lifespan of 521 years.

Considering that dinosaur fossils are over 65 million years old, the chances are astronomically slim in finding any useful biological materials such as DNA with dinosaur fossils. Even with or without Crichton’s methods as described in the books. However I will say this, dinosaurs could be theoretically cloned if a good amount of DNA from a particular specie is found. Perhaps in the future, if a method of re-amination & de-contaminating/purifying the contaminant DNA is discovered. And maybe, if an eccentric John Hammond-like billionaire finds the complete DNA sequence of a dinosaur at the same time, then Jurassic Park may be possible.

But ultimately if this situation does occur, cloning dinosaurs wouldn’t come as much of a surprise to many of us, since the better candidates such as the Wooly Mammoth and even the Moa would have already been cloned. This is due to frozen specimens that have been naturally preserved within permafrost in intact condition, unlike the dinosaurs. So it’s only natural that we would attempt to clone these extinct animals first.

The process of cloning a mammoth,simplified. Source: The Telegraph

However much like most of the children who saw the movie in the 90s, I simply did not know enough to realise or even care for the scientific inaccuracies. Regardless, now that I am aware I still don’t care to an extent, since Jurassic Park is after all, of a science fiction genre (not science fact). Hence why, to me Jurassic Park will forever be a genius piece of literary gold and a phenomenal movie of its time which pioneered in the combination of storytelling, CGI, and animatronics.

But the most demoralising thing for me is the conclusion that this Jurassic Park (as it was purely described in the books and films) strongly leans towards the impossibility.For we have barely perfected the cloning of non-extinct animals yet (see: dolly the sheep) let alone extinct animals. So for now, my childhood dream of seeing a living Brachiosaurus will seem a little farfetched. And that’s a bitter a pill for me to swallow.

Hijacking Chicken DNA. Photo: Dan Forbes; model maker: Jason Clay Lewis

But all is not lost, we have some reasonable questions left unanswered; can we find a large enough supply of preserved strands of Dino-DNA within fossilized bones to recreate dinosaurs? Or perhaps, could we tap into ancestral genes of animals present today to create dinosaurs? It might be a very long time until we find out these answers. But till then, is anyone up for a Pleistocene Park? Wooly Mammoths here we come.

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