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Resurrecting the Mammoth - skyblue1 - 03-14-2012 05:45 PM
Two teams of researchers have apparently gone on record as saying they plan on cloning the mammoth. In 2008, when the mammoth genome was announced in the journal Nature, we took at look at that possibility, and concluded it wouldn't work. Given the recent press attention, we thought we'd rerun an updated version of the relevant section from our original report.
Given that the genome is often called the blueprint for an organism, Nature took the liberty of commissioning an evaluation of what it would take to rebuild the mammoth using that blueprint. The challenge is enormous: each one of the mammoth's chromosomes are likely to be over 100 million base pairs long; the average surviving fragment of DNA we've obtained from mammoth remains is under 200 bases long.
That means the sort of cloning technique that we use on currently living mammals wouldn't work, since it relies on a genome that's largely intact. The cloned cells can undoubtedly repair some DNA damage, but nothing like the scrambled fragments we have from mammoths. There's always the chance that some mammoth remains contain larger fragments of DNA, but basic chemistry indicates that we're unlikely to ever find anything close to an intact chromosome.
So the piece suggests starting from scratch, using a process similar to the one that constructed the first artificial genome. Unfortunately, that bacterial genome is about three orders of magnitude smaller than a single mammoth chromosome, and the techniques used are simply unlikely to scale. Mammoths also had dozens of chromosomes, and we'd need to get two copies of each into a single cell, safely encapsulated in a nucleus. We've only got techniques that work for some of this, and we've never tried any of the ones that work on a task approaching this scale.
Assuming we have two full sets of mammoth chromosomes together in a single nucleus, advances in stem cell research suggest we could reset them to an embryonic stem cell state using molecular tools. Unfortunately, we still don't know how to get these stem cells to develop into adult organisms without implanting them into a viable egg or embryo. That would mean we'd need the embryo of a closely related species to work with.
It would obviously be best to do this with elephants (as the teams of researchers have realized), both as egg donors and surrogates. But, apparently thanks to an aquatic lifestyle in the elephant's evolutionary past, they have a baroque reproductive tract and an internal organ arrangement that makes laparoscopy to harvest eggs a non-starter. So, the elephant represents yet another technical hurdle.
There are a host of other issues that are relatively minor in scale—we'd need a Y chromosome and sequence from enough individuals to create a diverse breeding population—but resurrecting the mammoth faces some technological obstacles that we haven't yet even started to try to overcome. A more likely solution, Nature concludes, would be to identify the regions of the genome that have diverged most significantly between elephants and mammoths, and engineer the mammoth equivalent back into an elephant's DNA. Depending how well we can identify these, the mammophant that we produce may be at least physically indistinguishable from artists' renderings we're all familiar with.
Overall, Nature's analysis is pretty persuasive. Given the technology we have now, it's tough to imagine putting a mammoth together, even given the complete genome sequence.
But it's difficult to predict how technology advances will proceed. The article quotes one of the researchers who lead the efforts to sequence the Neanderthal and Denisovan genomes, Svante Paabo, as saying he doesn't expect to see anything more than a mammophant in his lifetime. Of course, Paabo's in his 50s, and I'd imagine that, in his 20s, he wouldn't have expected to see a Neanderthal genome completed in his lifetime. He has done just that.
http://arstechnica.com/science/news/2012/03/cloning-and-resurrecting-the-mammoth-not-so-fast.ars?clicked=related_right
RE: Resurrecting the Mammoth - BruceCM - 03-14-2012 06:27 PM
Ooh! Jurassic park, here we come? Uh, hope not!
RE: Resurrecting the Mammoth - skyblue1 - 03-14-2012 08:37 PM
of course Jurassic Park featured dinosaurs, instead of grazing mammals
RE: Resurrecting the Mammoth - BruceCM - 03-14-2012 08:40 PM
Sure, today the mammoth but it seems likely, if they start down that road, they're all too likely to end up with something more like the book/ film, don't you think?
RE: Resurrecting the Mammoth - skyblue1 - 03-14-2012 08:45 PM
that fantasy wont happen, IMO
RE: Resurrecting the Mammoth - BruceCM - 03-14-2012 08:50 PM
I sure hope not! Just don't have the apparent faith you do in scientists & whoever else gets involved. Not that they'd mean to create such a thing but they didn't mean to in the book/ film, did they? The theory of research might be sound & good, scientific methods might be very good & sound, most scientists might really mean well but even so, with the best motives & will in the world, it's too easy to imagine. Perhaps due to the imagination & writing skill of Michael Crichton or the skills of those who turned it into a very enjoyable film! But, as a possible reality, it's seriously scary & no fun at all, of course.
RE: Resurrecting the Mammoth - AspieGrrl - 03-15-2012 12:24 AM
The atmosphere is all wrong, anyway.
RE: Resurrecting the Mammoth - skyblue1 - 03-15-2012 12:42 AM
not as much oxygen by % as was 65 million years ago
RE: Resurrecting the Mammoth - Genesis - 03-15-2012 12:44 AM
I don't think its immune system would survive in this climate, or the fact that past cloned animals died from bacteria thats deadly to them....
RE: Resurrecting the Mammoth - AspieGrrl - 03-15-2012 06:48 AM
Well, I was speaking more about dinos, but yeah, it's a valid issue with the mammoths, too.
RE: Resurrecting the Mammoth - Genesis - 03-15-2012 06:51 AM
Yep....
RE: Resurrecting the Mammoth - BruceCM - 03-15-2012 09:24 AM
Good, let's hope some idiot genius doesn't find a solution/ way around that, then!
RE: Resurrecting the Mammoth - skyblue1 - 03-15-2012 05:50 PM
that genius would be one of the gods, if that were to happen
RE: Resurrecting the Mammoth - BruceCM - 03-16-2012 11:13 AM
RE: Resurrecting the Mammoth - Vampslord - 03-16-2012 05:05 PM
skyblue1 Wrote:
not as much oxygen by % as was 65 million years ago
You mean carbon right? Cause there was more carbon 65 million yrs ago.
Also mammoth lived from about 5 millions yrs ago to 4,500 yrs ago. Your only off by 60 millions years.
RE: Resurrecting the Mammoth - skyblue1 - 03-16-2012 06:23 PM
Vampslord Wrote:
skyblue1 Wrote:
not as much oxygen by % as was 65 million years ago
You mean carbon right? Cause there was more carbon 65 million yrs ago.
Also mammoth lived from about 5 millions yrs ago to 4,500 yrs ago. Your only off by 60 millions years.
I was speaking about why cloned dinos wouldnt live very long today
or at he very least, they would be dwarves compared to their ancestors
oxygen content was much higher back in those days
one reason why some of them were so gigantic
RE: Resurrecting the Mammoth - Vampslord - 03-17-2012 04:36 AM
Ah ok. tought you were still talking about mammoth.