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Although it’s fun to fantasize about dinosaurs
in a modern zoo--being able to touch them and hear
them and watch them--cloning dinosaurs from prehistoric
DNA trapped in petrified insects is, unfortunately,
impossible, for several reasons.
To begin with, it’s extremely difficult to
find DNA from prehistoric times, even if it was
trapped in a bug inside amber. Even if the insect
died immediately after sucking dinosaur blood, the
stomach acid would keep digesting the food with
the DNA in it. DNA is very fragile when exposed
to the air (the oxygen damages it; it’s even
hard to keep DNA together in a laboratory, let alone
a 160 million year old insect!). Of course, finding
ancient DNA isn’t impossible; paleontologist
Jack Horner has found some.
Prehistoric DNA is a novelty, though--nothing
can be done with it, scientifically. The largest
quantity found so far is a sequence of merely 250
base pairs which is nothing compared to the 1 -
10 billion it takes to make a single organism. Besides,
scientists have no clue as to what dinosaur DNA
should look like; yes, they know it’s made
of the same material as all other DNA, but the exact
sequence isn’t known, and the sequence is everything,
when it comes to cloning. That means that scientists
couldn’t add known DNA sequences (say from
another reptile or bird) to make a full strand,
either.
The DNA isn’t the only problem, though: one
also has to consider things such as food and environment.
If a dinosaur ever were to be cloned, zookeepers
would have no way to feed the herbivores (plant
eaters; it has been suggested that the meat-eating
dinosaurs would have no problem because the chemical
composition of meat probably hasn’t changed
much). Plants constantly develop poisons and other
protective measures to prevent being eaten. Dinosaurs
wouldn’t be able to adapt (whereas modern animals
have been able to over the past millions of years,
dinosaurs have not because they’ve been extinct)
to these threats and would die after the first meal.
The biggest threat to a newly cloned dinosaur, however,
would be disease. Since the last dinosaur died 65
million years ago, bacteria and viruses have changed
drastically; an infected dinosaur would have no
means of defense against any modern microbes.
These are just the main reasons why scientists
can’t clone dinosaurs, but the list goes on
and on. For now, dinosaurs will simply have to be
content with remaining in our imaginations.
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