Xerxes said:
Actually, they can piece it together by taking lots of degraded DNA and filling in the blanks. Takes time, but it can be done.
No, actually they cannot. You’re thinking of “Jurassic Park” which was science fiction. We're not even close to being able to "piece together" entire genomes of complex animals.
valich said:
I thought that if it was frozen as such, that it can still be deciphered?
There’s
frozen and then there’s
frozen, if you understand what I mean. For just about all
in vitro molecular biology applications, some DNA degradation can be tolerated. But when it comes to cloning a whole new animal by nuclear transfer, what you are trying to do is produce an entire new animal from a single cell. This requires every gene and every chromosome to be perfectly intact, otherwise development doesn’t work. When animal cloning is performed in the lab it utilizes living cells. In the few instances where a dead animal has been cloned, the donor cells were either (i) obtained and used as living cells before the animal died, or (ii) cells from the animal were meticulously prepared and snap frozen in liquid nitrogen before or immediately after it died. Freezing in liquid nitrogen is the only way that the nuclear DNA in the donor cells will remain intact enough for this application. Although Siberian tundra is very cold, the cells of a mammoth will not have been snap frozen in the same way as is performed in the lab. The DNA will have undergone some degradation. Maybe not much, but certainly too much to perform cloning by nuclear transfer. There is no way (with current technology) that the frozen mammoth can be cloned. Any other method of preservation (formaldehyde, ethanol etc) will allow way too much DNA degradation.
Edit:
addition of extra info
I just noticed this quotation above. It is an example of what I was talking about:
…and discovered its related more to the indian elephant rather than previously believed african elephant.
Despite some degradation, the DNA recovered from the mammoth would have been intact enough for most routine molecular biology manipulations, such as DNA sequencing. It was obviously possible to sequence some portions of the mammoth DNA and compare the sequences to extant elephants, thus determining its relatedness to Indian elephants. But just because this can be accomplished does not mean that you can clone a whole new mammoth via nuclear transfer. That’s an entirely different 'kettle of fish'.
When asked if they could grow a woolly mammoth or clone it the scientist blinked a number of times and said: “we're closer to doing that, but the problem is, when you have one walking around, where do you put it and what do you do with it?”
I can assure you that the scientist (if, in fact, this was a genuine scientist – always remember to treat scientific info gained from mass media science reports with a grain of salt) was hyping for the media. A similar scenario played out in Australia recently. Scientists have a preserved thylacine embryo (“Tasmanian Tiger”) in a jar from almost a century ago and had been saying for over 5 years that there were going to clone it. They have been extinct since the early 20th century. Every few months they would play up to the media with reports of how they were “getting closer”. This year the team of scientists officially abandoned the project because (surprise surprise) the DNA was too fragmented in all the cells. This is exactly what every knowledgeable scientist had been saying would be the case, and I’ll bet my last dollar that they knew it all along as well. But they got what they wanted: media exposure. Any scientist who talks about cloning a mammoth is doing exactly the same thing.
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