Re: Species Resurrection

Tim Tyler <seemysig@xxxxxxxxxxxxxx> wrote:
DK wrote:
Tim Tyler <seemysig@xxxxxxxxxxxxxx> wrote: [...]

--> http://timtyler.org/species_resurrection/ <--

The essay starts:

Resurrecting species that had previously been thought extinct now seems
to be quite technically possible.

Not a chance. All modern technologies require you to come up,
as a bare minimum, with chromosomes, not just with DNA sequences.
That means all the DNA methylation, all the histones and auxillary
proteins present in the right places in right amounts all with proper
modifications. No way.

Well it hasn't been done /yet/.

My piece was triggered in part by a recent news story:

``Scientists in Maryland have already built the world's first
entirely handcrafted chromosome ? a large looping strand of
DNA made from scratch in a laboratory, containing all the
instructions a microbe needs to live and reproduce.

In the coming year, they hope to transplant it into a cell,
where it is expected to "boot itself up," like software
downloaded from the Internet, and cajole the waiting cell
to do its bidding. And while the first synthetic chromosome
is a plagiarized version of a natural one, others that code
for life-forms that have never existed before are already
under construction.

http://www.dentonrc.com/sharedcontent/dws/dn/latestnews/stories/121707dnnatsynb
io.2bf46e0.html

....as well as by the sequencing of the genome of one extinct
species.

Sequencing is trivial in comparison to expression.

Look, my point was that your comment "quite technically possible"
was clearly wrong. You list a bunch of extinct mammals and
as an illustration of that this idea is possible provide very simple
bacterial chromosome experiment that wasn't even performed.

You know that there is huge difference between bacterial
chromosome and eukariotic genome. You know there is a
big difference between "quite possible" and "they hope" or
"it is expected".

Species resurrection now looks to be pretty clearly in the
forseeable future -

Future - maybe, foreseeable - hardly.

and that's interesting not least of all
because Homo floresiensis and Neanderthal man may well prove
to be within reach:

``Unleashing a new kind of DNA analyzer on a 38,000-year-old
fragment of fossilized Neanderthal bone, scientists have
reconstructed a portion of that creature's genetic code -
a technological tour de force that has researchers convinced
they will soon know the entire DNA sequence of the closest
cousin humans ever had.''

http://www.washingtonpost.com/wp-dyn/content/article/2006/11/15/AR2006111501042
.html

Once again, this is a huge advance and all that. Maybe, just
maybe, most of the Neanderthal genome will one day be sequenced.

But the devil is in the details. And thus far the details are: 1) There is a
lot of disagreement on what is signal and what is contamination or
sequencing errors, 2) only small bits of few individual genes had been
positively identified, 3) chemistry of DNA preservation sets its limits -
if there is no DNA to begin with, sequencing it is gonna be problematic.
4) getting non-coding sequences right is a lot more trouble than
known ORFs.

DK

.

Relevant Pages

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