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Extinct Species and DNA
Name: Nathaniel
Status: Student
Grade: 9-12
Location: VA
Country: United States
Date: June 2007
Question:
Is it possible to extract DNA from mummified skin or
amber? If so how close are we from
recreating an extinct species?
Replies:
Nathaniel,
Even if we were able to extract sufficient successful DNA to
"re"produce such an organism, and even if we could produce one
of each sex, such a species would have trouble repopulating a
species, because there would be very low genetic diversity.
Any genetic problem or potential disease could quickly bring
down the entire (small) population.
In my opinion, the only hope for reproducing such a species
would be to find a lot of DNA from a lot of members of the
species. This would enable, assuming successful capture of
the inherent DNA, re-production of a species with enough
genetic diversity to allow for interbreeding without the
typical problems of relation/sibling interbreeding.
Thanks for using NEWTON!
Ric Rupnik
You can extract DNA from mummified remains and other old samples in some
cases. However, in nearly every case the DNA is degraded, damaged, or only
partially recoverable. Even if we recovered all the DNA intact, making the
organism from its DNA is not something people know how to do, and are very,
very far away from knowing it as well.
DNA is not quite a "blueprint" for an organism. It's not like a plan with
directions on how to make an organism. There are many, many complicated
interactions between chemicals in our bodies, and they depend on
concentration. DNA is only a very small portion of the information needed to
fully understand and make a living organism. And there are important
theological questions related to this as well, which I will avoid for now.
As an example, look at the ingredients list on the side of a package of
bread. If someone only gave you that list, could you make the bread? You
might experiment with amounts, but how would you know that you had to bake
the bread (the ingredients don't tell you anything about technique)? How
would you know their order of mixing? DNA is like a list of hundreds of
thousands of ingredients, except it's even more of a struggle because 1)
we're not sure where one ingredient name stops and another begins, 2) the
list is incomplete -- some ingredients get modified/changed/combined later,
3) the ingredients aren't in any kind of order (e.g. not in order of
decreasing amount), 4) we don't know what order, amount, or what technique
to combine them (some ingredients get used many times over, and they have
different functions depending on where they are), 6) we couldn't necessarily
make the amazingly complex structures of organisms even if we had all the
right ingredients and amounts.
Alternatively, if the DNA you found were similar to a current organism, you
might try to 'engineer' certain genes into that organism. It's very hard to
engineer one gene, let alone multiple genes, though. Even then, the results
may be very unlike what you expect -- the function of genes depends a great
deal on where it is, how it's used, and what else is around it. One gene in
one organism may not work the same in another organism.
I guess I'm saying this is just too complicated for us to achieve now, or
any time soon. In the future, we may develop this knowledge -- it's probably
not "impossible", but it's not imminent.
Hope this helps,
Burr
Even if we were able to extract DNA from an extinct species this doesn't
mean that it would spontaneously assemble itself into an organism. There
are many many more hurdles to overcome before that can happen. DNA needs
to reside in a cell, and will need to be in an egg that can be fertilized.
It would then need to be grown inside a surrogate mother. These are just a
few of the steps.
vanhoeck
Jurassic Park notwithstanding, any DNA that would be extracted from fossils
would almost certainly be highly fragmented and therefore not suitable for
cloning an entire organism. A typical eukaryotic cell contains several
billion base pairs worth of DNA distributed amongst 50 chromosomes, and
each of these 50 DNA molecules would have been been originally comprised
of approximately 40 million base pairs worth of DNA.
Ron Baker, Ph.D.
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Update: June 2012
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