Could We Clone Dinosaurs as in Jurassic Park?:
The short answer is, “no.”
According to
Jurassic Park, they got dinosaur DNA by extracting it from mosquitoes. Now it’s true that mosquitoes lived during the Mesozoic, and presumably they sucked blood from dinosaurs. Female mosquitoes suck blood because they need it to produce eggs, and this was doubtless true during the Mesozoic, as it is now. Occasionally, a mosquito will get trapped in tree sap that eventually fossilizes and becomes amber, thus preserving the unfortunate insect. But to my knowledge, only
one mosquito has so far been found in amber that dates back to the Mesozoic Era.
Just because the mosquito died when it got trapped wouldn’t cause the digestive enzymes in its gut to stop working. So, even if a mosquito took a drink of dinosaur blood then immediately got itself trapped in sap that ultimately turned into amber, the DNA in the mosquito’s gut would be seriously degraded by the mosquito’s digestive enzymes.
On top of that, DNA isn’t all that stable, and tends to break down over time even under the best of circumstances. There have been some
very controversial reports of scientists extracting
fragments of DNA from insects preserved in amber, but no one claims to have been able to recover anything even
remotely resembling a complete DNA strand in this way. It would be astonishing to recover even
one percent of a 100-million-year-old DNA strand from a mosquito’s gut (assuming anyone even
found a preserved mosquito that old), much less the 99 percent or so that the movie implies they were able to recover. Suffice it to say that for practical purposes, it is — and almost certainly forever will be — impossible to recover anything remotely approaching a complete DNA sequence from 100-million-year-old samples.
Even if you somehow
did manage to get 99% of a dinosaur’s DNA, that missing 1% is important! After all, there are something like 3
billion base codes in a typical vertebrate’s genome. That’s 30
million substitutions you would need to make in order to complete the animal’s genome — in 4
30000000 possible combinations! Keep in mind that the vast majority of combinations you’d come up with would surely result not in a dinosaur with some interesting behavioral quirks, but something that’s
dead. Any
one of those substitutions could cause a lethal mutation, and you’re making 30,000,000 substitutions! The odds of you winding up with a living animal are remote, to say the least.
And getting the DNA would actually be the
easy part! Despite what most people seem to think, DNA is
not a “blueprint” for a living thing. A much more accurate analogy would be to say that DNA is a “recipe” for a living organism. It specifies the broad outlines of an organism’s development, but not every little detail. DNA doesn’t contain
nearly enough information to exactly specify the layout of an animal’s nervous or circulatory systems, for instance. It’s more like a set of instructions along the lines of “put some nerves in this general area” and so forth. That’s why even identical twins don’t have the same fingerprints or circulatory layouts, even though they have identical DNA.
By itself, the DNA would be quite useless. DNA works because enzymes present in the cells activate specific sections of DNA at the proper times and in the proper sequences. In other words, even if you somehow got a complete DNA sequence from a dinosaur, it would be utterly useless unless you also had a
dinosaur egg to put it into, complete with all the proper enzymes. Good luck finding one!
It’s highly unlikely that a
single piece of amber exists anywhere on the planet with a mosquito preserved inside so perfectly that it would be possible to extract a dinosaur’s complete DNA makeup from the blood in said mosquito’s gut. Even if there is, you’d still need an intact egg from that species of dinosaur to put it into. So, I think it’s safe to say that no one will ever clone a dinosaur.
Having said that, there’s no particular reason to expect that we won’t eventually know enough about genetics and developmental biology that we’ll be able to
recreate dinosaurs. But those re-created “dinosaurs” would only represent our best guesses about how real dinosaurs looked and behaved. Who knows how accurate those guesses would be?
Could We Clone Dinosaurs?
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