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Cenozoic Park: Cloning the Tasmanian Tiger
Mirk writes "The
Australian Museum
reports a breakthrough in their plans to clone the Tasmanian Tiger. The ``tiger'', actually a carnivorous marsupial, became extinct in 1936, when the last known
specimen died in captivity. Er, did I say ``extinct''?
Now it looks like what everyone thought was an extinction may be
``a 70-year hiccup'', to quote the press release. The museum's Evolutionary Biology Unit have successfully replicated individual Tasmanian Tiger genes using a process known as
PCR (Polymerase Chain Reaction)."
You can find out more about "Tasmanian Tigers" at The Thylacine Museum. In reality it's a marsupial, not a mammal, and so it's closer to an opossum than a feline like a tiger. The only reason it's called a "tiger" is because of its stripes, as seen in the photo at the top of this webpage about mysterious animals. And it may not even be extinct...
PCR doesnt get you a clone
you need a host egg and the actual DNA I would like to see them synthsize it but somehow I dont think so
regards
john jones
I'm capped, and yet I still whore.
DNA, as I'm sure we all know, is double stranded. One strand is a complement of the other. A complements T and C complements G. So, if one strand is:
5' ATTTC 3'
then the other strand is:
3' TAAAG 5'
The DNA is "read" from 5' to 3'. 5' and 3' refer to particular atoms on the sugar backbone that are attached to one another via a phosphate.
When DNA is replicated, you split it into two strands:
5' ATTTC 3' and 5' GAAAT 3'
(notice that the two complements read in opposite directions)
and each strand has it's complement added.
5' ATTTC 3' and 5' GAAAT 3'
3' TAAAG 3' and 3' CTTTA 5'
The problem with this is, in order for this happen to DNA, you need an RNA "primer." This primer is a complement to the beggining of what you want to replicate. So, for example, if you have (RNA bases I'm putting in bold. U is the same as T:)
UAA
floating around in solution, which compliments ATT, then any sequence beggining with ATT will be replicated, but other sequences will NOT be replicated, because no RNA primer is available to get them started.
So, if you have a whole mess of DNA, including a piece that you're interested in, which reads:
5' ATTTG (long space........) TCGTC 3'
3' TAAAC (long space........) AGGAG 5'
and you add:
TAAAC and TCGTC
You get a chain reaction; the sequence flanked by the complements of the two things you add (the sequence printed above) is replicated, and then the replication product is replicated, and so on and so on. Other sequences, which are flanked by only one compliment (only ATTTG, say) will be replicated occasionally, but there replication products cannot in turn replicate, so you get no chain reaction.
More history here.
A thermophile (heat loving organism), thermus aquaticus, provided a polymerase (an enzyme which polymerises, that is to say replicates sequences of, nucleic acids like DNA and RNA) that works extremely fast at high temperatures. In general, the higher the temperature you run a reaction at, the faster it goes. However, most biological enzymes (from, say, a person) cease to function when temperatures rise (this is one of the ways heat kills you.) Thermophiles, bacteria that live in geysers and in volcanic ocean vents, have evolved enzymes that continue to function at higher temperatures.
The good and new comes from no quarter where it is looked for, and is always something different from what is expected.
The Sydney Morning Herald have just done an article on this. While it doesn't cover much more than the one linked in the article, it has links to some other SMH articles. One Of them is an interview with one of the main scientists behind it, and is quite insightful. The other is a gallery of relevent photos.
This post will enter the public domain 70 years after my death, unless Disney buys another extension.
That's human mitocondrial DNA. The mitocondrial Eve is not our common ancestor, or even our common genetic ancestor. She is the most recent common ancester of all humans alive on earth today w.r.t. matrilineal descent. See the BBC explanation for further enlightenment. The existence of the Mitochondrial Eve is a mathematical fact (unless something like a multiple-origins theory of human evolution i.e. the human species arose independently in different geographically separated populations, and that the present-day ease of interbreeding is the result of a remarkable convergent evolution, is true. Few people subscribe to the multiple-origins theory, and the Mitochondrial Eve observation is a refutation of multiple-origins). Since she has been identified as well (as much as possible,) this is not a theory.
That said, the chances of mutation from breeding two related individuals may be higher than those of unrelated individuals, but they are not absolute certainties. Some degree of variation can be recovered, and while that may not be a huge amount of variation, it's more than they've currently got.
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The Tassie devil has been suggested as a host. The big advantage for the thylacine, and the reason why it will probably be the first successful recovery, is that it is a marsupial, which means it is born when it is basically still a foetus. This means that the host animal can be kept on immunosuppressants for the short duration of pregnancy without rejecting the embyo or getting too screwed up itself. Something like a mammoth, on the other hand, would need to be carried for 18 months inside what would end up being a very sick elephant.
His statement makes perfect sense, you just have trouble accepting it.
-- this is not a