And so it begins.
BEC CREW
24 MAR 2015
Scientists have been discussing and debating over it for years, and now the
first real step towards bringing the extinct woolly mammoth back from the dead is complete.
A
renowned geneticist in the US has extracted DNA from the frozen remains of a long-dead mammoth found on Wrangel Island in the Arctic Ocean, created a synthetic replica of it, and implanted it into elephant cells that have been isolated in a petri dish, using a new technique of DNA splicing that allows for unprecedented accuracy. He reports that, so far, the altered elephant cells have been functioning perfectly.
Lead scientist George Church, a professor of genetics at Harvard University, and
his team weren’t able to synthesise the entire woolly mammoth genome, but instead selected genes that encoded particularly ‘mammoth-like’ characteristics, such as cold-busting fat, ear size, and a woolly coat.
"We
prioritised genes
associated with cold resistance including hairiness, ear size, subcutaneous fat and, especially haemoglobin,"
Church told Ben Webster at The Sunday Times. Haemoglobin is what scientists think
helped the mammoths survive such a frigid climate thousands of years ago. "We now have
functioning elephant cells with mammoth DNA in them. We have not published it in a scientific journal because
there is more work to do, but we plan to do so."
If Church’s experiments go as planned, this could be the first time we see a woolly mammoth alive in more than 3,300 years.
The technique used to
join synthetic mammoth DNA fragments with the genetic code of an elephant is called CRISPR/Cas9, and while it’s been recently used to create transgenic organisms, this is the first time it’s been used on the DNA of an extinct organism.
The next step will be for the team to
figure out how to replicate the process using elephant cells in situ, rather than in a petri dish. If they can do that
using elephant eggs, they could
theoretically produce an
elephant with mammoth traits. But that’s a
big “if”. And is that something we really want to do? As biologist Alex Greenwood from the Leibniz Institute for Zoo and Wildlife Research in the US
told Sarah Knapton at The Telegraph:
"We face the potential extinction of African and Asian elephants. Why bring back another elephantid from extinction when we cannot even keep the ones that are not extinct around? What is the message? We can be as irresponsible with the environment as we want. Then we'll just clone things back?
Money would be better spent focusing on conserving what we do have than spending it on an animal that has been extinct for thousands of years."
Three separate teams around the world are working on resurrecting the woolly mammoth right now, so the
ethical conversation might be too late, but at least we’re having it.
It’s often pretty redundant to discuss how funds for one scientific experiment could be better served elsewhere because it’s a whole lot more complicated than that. But I think
in this case it’s pretty valid. We’re never going to stop the mammoth revival train - unless of course we make it illegal - but anything to get endangered animals into the spotlight has to be valuable.
Sources: The Telegraph, The Sunday Times
Mammoth DNA has been implanted into functioning elephant cells - ScienceAlert
This is slightly exciting and scary...I mean the article -at least to me doesnt reveal enough to feed on. I know splicing method infact have used it (though not CRISPR/Cas9 nor at this level more at gene level than genome level) and study it in situ (again not organism level and def not animals)...
However, I agree money should be spent on conserving what we have than reviving one that is long dead!
For those who want to know more of this CRISPR/Cas 9 thing : CRISPR/Cas9 and Targeted Genome Editing:A New Era in Molecular Biology | NEB
In the acquisition phase, foreign DNA is incorporated into the bacterial genome at the CRISPR loci. CRISPR loci is then transcribed and processed into crRNA during crRNA biogenesis. During interference, Cas9 endonuclease complexed with a crRNA and separate tracrRNA cleaves foreign DNA containing a 20-nucleotide crRNA complementary sequence adjacent to the PAM sequence. (Figure not drawn to scale.)
A. Wild-type Cas9 nuclease site specifically cleaves double-stranded DNA activating double-strand break repair machinery. In the absence of a homologous repair template non-homologous end joining can result in indels disrupting the target sequence. Alternatively, precise mutations and knock-ins can be made by providing a homologous repair template and exploiting the homology directed repair pathway.
B. Mutated Cas9 makes a site specific single-strand nick. Two sgRNA can be used to introduce a staggered double-stranded break which can then undergo homology directed repair.
C. Nuclease-deficient Cas9 can be fused with various effector domains allowing specific localization. For example, transcriptional activators, repressors, and fluorescent proteins.
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