It took fifty years, but DNA work is now breaking through the
threshold of engineering fresh synthetic DNA that can be used to
augment the natural genomes themselves. We will have to get it
right, but there is plenty of evidence out there that this is very
possible and has been achieved once already by humanity. The
interesting question may be to determine just how much of the human
genome itself was artificially modified when we began populating the
Earth as agricultural man.
It may be possible to winkle out some small pockets of humanity as
yet uncrossed with the modern genome, although I suspect that that is
a hopeless proposition.
I have posted in the past that the ET of a large number of UFO
encounters appear to be approximately what a human modified for space
would look like. ET is able to have reasonable mobility in our
gravity well but can not be called upon for the heavy lifting Earth
demands.
When mankind decides to populate habitats in space, it will be
appropriate to produce a space modified human being to do so.
June 06, 2012
An international team
of researchers discovered that the body's copying machine for DNA
works in the same way for manmade, artificial building blocks of DNA
as it does for the natural kind.
If scientists find
artificial DNA building blocks work well and are safe to use, the
extra building materials could create DNA that codes for new
molecules that the body can't make now. The artificial DNA could also
form the basis of a partly synthetic organism.
The DNA code in living things is made of four different molecules, called bases, that are nicknamed A, T, C and G. In a double row of DNA, the bases always link up to each other in a specific way, with A's matching with T's and C's matching with G's. In 2008, a team of researchers created a third, artificial pair of DNA molecules made to match with each other, named NaM and 5SICS. In this new study, some of the same researchers used a technique called X-ray crystallography to take pictures of A, T, C, G, NaM and 5SICS while they were getting copied in a test tube.
KlenTaq polymerase induces the dNaM-d5SICS unnatural base pair to adopt a natural, Watson-Crick–like structure.
Nature Chemical Biology - KlenTaq polymerase replicates unnatural base pairs by inducing a Watson-Crick geometry
Many candidate
unnatural DNA base pairs have been developed, but some of the
best-replicated pairs adopt intercalated structures in free DNA that
are difficult to reconcile with known mechanisms of polymerase
recognition. Here we present crystal structures of KlenTaq DNA
polymerase at different stages of replication for one such pair,
dNaM-d5SICS, and show that efficient replication results from the
polymerase itself, inducing the required natural-like structure.
In the future,
artificial DNA building blocks like NaM and 5SICS could expand the
well-known "A, C, G, T" vocabulary of DNA, according to a
statement from the Scripps Institute. Synthetic bases may work even
if they aren't shaped like natural bases, as long as they have
flexible chemical bonds, the way NaM and 5SICS do.
Romesberg, Malyshev and their colleagues are now working on tweaking NaM and 5SICS so that natural DNA strands with those synthetic bases added will copy even more efficiently, at a rate that's closer to the rate found in all-natural DNA, they wrote in their paper. Once they accomplish that, they can start building synthetic organisms from the ground up. "If we can get this new base pair to replicate with high efficiency and fidelity in vivo [i.e., in a living organism], we'll have a semi-synthetic organism," Romesberg said.
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