As I'm sure you are aware, my favourite film is Jurassic Park (I've probably mentioned it ad nauseum - this is the last time I mention it (promise)). At the time, the idea of cloning dinosaurs to bring them back was pure fantasy, something that the scientific community were quick to point out. But, 20 years on, is it still fantasy or is there some truth to it? Let's find out!
First of all what is cloning? According to wikipedia, cloning is the process of producing similar (this is an important word) populations of genetically identical individuals. The predominant method used is known as Somatic Cell Nuclear Transfer (or SCNT for short). This involves transferring the nucleus of an adult cell (known as a somatic cell) to an egg cell that has no nucleus.
In this picture of an animal cell, the nucleus is the big blue sphere. This is where the DNA is kept in Eukaryotes (animals, plants, fungi and some other funky things like algae and amoebae).
Once the nucleus has been transferred into the egg cell, it is then observed. If the cell starts to divide normally, the cell is placed into the uterus of a donor mother. It is at this early stage the clone ceases to be exactly identical to the original because every time a cell divides, there is a chance the DNA can mutate. Also, only the nuclear DNA is transferred. There is also DNA in the mitochondria (singular, mitochondrion, the pinky capsules with wavy things in them in the above picture). The clone's mitochondrial DNA is obtained from the surrogate mother, again ensuring that the clone will not be exactly the same as the original. The mitochondrial DNA is used to determine which proteins an organism can obtain energy from in the form of food. As a result, they are very important.
So this raises a few questions regarding dinosaur cloning. Has dinosaur DNA been recovered and what would we use as the surrogate mother?
Let's look at the first question. Has Dinosaur DNA ever been recovered. The answer to that is no. There has been DNA recovered from blood-sucking insects from the dinosaur times, but it's only a few strands - impossible to know whether it's from a dinosaur, pterosaur, or even the insect itself. Besides, we would need a whole genome to be able to clone a dinosaur. However, dinosaur DNA from bones has been reported but it is extremely controversial. It all started in 1994 when three American palaeontologists, Scott Woodward, Nathan Weyand and Mark Bunnell, claimed to have found the DNA in bone fragments from the Blackhawk Formation in Utah. Woodward et al. did not identify which dinosaur the fragments came from (they weren't even able to prove they were dinosaur bones anyway and the pictures used in the paper are very bad quality). But the claim was there. 80 million-year-old DNA. The following year, S. Blair Hedges and Mary Schweitzer published a rebuttal, in which they were able to show that the "ancient DNA" was in fact human DNA that had contaminated the bone (maybe someone cut themselves while handling the bones?).
However, later that same year, a group of Chinese scientists again made the claim of discovered DNA from dinosaur egg shells. Unfortunately, they published their findings in an obscure Chinese journal which no-one read and so it escaped the scientific community (An, et al., 2005, cited in Wang, et al., 1997). That was until 1997 when another group of Chinese scientists tested the DNA and, just like Hedges and Schweitzer, found the DNA to be contaminated - this time with plant and fungi DNA (Wang, Yan and Jin, 1997).
And that's it. They're the only claims of Dino DNA I know of. It seems to have been a very 90s phenomenon. I suppose the discovery of all those dino-birds in the early 00s seems to have distracted the scientific community.
The second question is a bit easier and at the same time harder to answer. The ideal surrogate mother would be another dinosaur but as they're largely extinct that could be a bit difficult. However, birds would be a good alternative. Unfortunately, the only way to know is to try it and since it would be impractical and unethical at the moment, we're probably never going to know.
So, in conclusion, while cloning a dinosaur would not be impossible in theory, the lack of any genuine dinosaur DNA and knowledge of the biochemistry of dinosaurs prevents us from being able to achieve it. In part 2, I will look at another issue of Jurassic Park that gets a lot of nerds angry on the internet. The raptors. For next week's exciting outing, we'll be looking at the functional morphology of three different dinosaurs.
See also
More dinosaurs
More Jurassic Park
However, later that same year, a group of Chinese scientists again made the claim of discovered DNA from dinosaur egg shells. Unfortunately, they published their findings in an obscure Chinese journal which no-one read and so it escaped the scientific community (An, et al., 2005, cited in Wang, et al., 1997). That was until 1997 when another group of Chinese scientists tested the DNA and, just like Hedges and Schweitzer, found the DNA to be contaminated - this time with plant and fungi DNA (Wang, Yan and Jin, 1997).
And that's it. They're the only claims of Dino DNA I know of. It seems to have been a very 90s phenomenon. I suppose the discovery of all those dino-birds in the early 00s seems to have distracted the scientific community.
The second question is a bit easier and at the same time harder to answer. The ideal surrogate mother would be another dinosaur but as they're largely extinct that could be a bit difficult. However, birds would be a good alternative. Unfortunately, the only way to know is to try it and since it would be impractical and unethical at the moment, we're probably never going to know.
So, in conclusion, while cloning a dinosaur would not be impossible in theory, the lack of any genuine dinosaur DNA and knowledge of the biochemistry of dinosaurs prevents us from being able to achieve it. In part 2, I will look at another issue of Jurassic Park that gets a lot of nerds angry on the internet. The raptors. For next week's exciting outing, we'll be looking at the functional morphology of three different dinosaurs.
See also
More dinosaurs
More Jurassic Park
References
Hedges, S. B. and Schweitzer, M. H., (1995) 'Detecting Dinosaur DNA' Science, 268 (5214) pp. 1191-1192, doi: 10.1126/science.7761839
Wang, H-L., Yan, Z-Y. and Jin, D-Y. (1997) 'Reanalysis of Published DNA Sequence Amplified from Cretaceous Dinosaur Egg Fossil', Molecular Biology and Evolution, 14 (5), pp. 589-591
Hedges, S. B. and Schweitzer, M. H., (1995) 'Detecting Dinosaur DNA' Science, 268 (5214) pp. 1191-1192, doi: 10.1126/science.7761839
Wang, H-L., Yan, Z-Y. and Jin, D-Y. (1997) 'Reanalysis of Published DNA Sequence Amplified from Cretaceous Dinosaur Egg Fossil', Molecular Biology and Evolution, 14 (5), pp. 589-591
Woodward, S. R., Weyand, N. J. and Bunnell, M. (1994) 'DNA Sequence from Cretaceous Period Bone Fragments', Science, 266 (5188), pp. 1229-1232
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