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Wooly Mammoth Extracted Intact From Siberian Ice
Lawrence_Bird writes ... a group of scientists have extracted a wooly mammoth intact from a Siberian icefield. "They used a radar imaging technique to `see' the mammoth in its icy grave, then excavated a huge block of frozen dirt around it to preserve the 23,000-year-old creature." See the dailynews.yahoo story. Naturally, there's talk of cloning the thing. If the effort succeeds, will McDonald's sell McMammoth burgers?
Argghh! We've been through this.
Of course the mitochondrial DNA was from the host cell. They knew it would be and didn't really care. It's not a big thing. Mitochondria are mitochondria, they change tranportable blood fuel into usable cell fuel (I'm just not up to big words like glucose tonight). A mammoth with modern elephant (or cow, or pig, or sheep) mitochondria is a mammoth as far as I'm concerned.
(now that that's out of my system...)
The Dolly technique is crusty in other ways, but it should work well enough to get some hairy elephants walking around northern Asia. Well, not quite the Dolly technique... this requires something a little more complicated, but IMHO doable in a year or two with enough money (or ten years from now in somebody's back yard).
I'd agree with you on the DNA bit, but they've got a whole mammoth. That's one heck of a DNA sample! They should be able to patch up the cracks with that big a sample.
Introducing an element that was once part of [an ecosystem], but is no longer is does just as much harm to an ecosystem as introducing a specimen that has never been there at all.
That's speculation. The former has never been done before. The latter has been done many times (sometimes deliberately, sometimes inadvertently; sometimes by humans, sometimes by wind, ocean currents, etc.) with varying results.
Speculation is a good thing - we ought to consider all the possibilities before reintroducing an extinct species - but it's still speculation. It is by no means certain that it will be disasterous, as the introduction on non-native species has frequently been.
If we re-introduce Wooly Mammoths into nature, we don't know how well they will adapt, and we don't know how well nature will adapt around them.
True, but consider. Mammoths are much like present-day elephants. Megafauna. Long-lived. Few predators. Slow maturation. Slow reproduction. What population biologists would call K-strategists. Introduced species that become a problem for native ones are almost invariably r-strategists (A notable exception being the most invasive species of all - humans). R-strategists are typically small creatures. Short-lived. Normally subject to intense predation in their native environment. Rapid maturation. Very rapid reproduction. These things combine to give introduced species an edge in their new, predator-free environments. They're not likely to be a problem in the case of wooly mammoths.
Cloned wooly mammoths would probably not be released into the wild right away, but kept in zoos, or penned up on research farms for study. Given their slow rate of reproduction, it'd be a very long time before there were enough of them to have much of an impact on their environment.
One more thing - wooly mammoths have probably been extinct for only a few thousand years. As no other creature has appeared to fill the niche previously occupied by the mammoths in that short time, I suspect their reintroduction to Siberia would have little negative impact, assuming they ever were released (or escaped) into the wild.
So far as I've read, one of the biggest obstacles in undertaking this whole cloning thing is that it's going to take a long time before we see any results. Assuming we are able to impregnate an elephant with a mammoth or half-mammoth zygote, the gestation period of an elephant is anywhere from 600 to 760 days(!), and it takes ten or twelve years for an elephant calf to reach sexual maturity. Even if everything goes according to plan, we won't know if we have a viable mammoth (or half-mammoth) for well over a decade after conception.
Regards,
I'm skeptical about cloning ancient things from their DNA. DNA, even more than most macromolecules, needs to be constantly repaired. If you leave DNA sitting around it will slowly lose its properties. For example, UV light causes a process called pyrimidine dimerization where adjacent pyrimidine bases fuse in a specific manner. It is estimated that we have over 10,000 pyrimidine dimerization events that happen every day in our bodies, all of which are quickly and systematically repaired. This is simply one example of a way in which DNA can become damaged if not fixed constantly -- there are others. Something I never hear from the proponents of such techniques is how they get the info INTACT.
Granted, the DNA may be good enough to do RFLiPs or other restriction enzyme digestion technique and get reasonable data. But, and this is a big but, for a diploid organism to work properly we need (two) copies of each gene that will be used to work. I, as a biochemist, don't believe that we have the ability to isolate two copies of nearly perfect DNA....
-- Moondog