Replacing DNA
Rafe Furst
Tuesday, 03 March 2009 00:02 UTC
Recently a breakthrough in cultivating stem cells was announced which involved replacing DNA in existing cells to essentially “reprogram” the cell into a stem cell.
Let’s suppose you could design a nanobot which could detect the entire chromosome set within a single cell and give a pass/fail test for the following (a) the structure matches a known “clean” copy; (b) there does not exist extraneous genetic material in the nucleus. Let’s also suppose that the nanobot could either destroy the cell, or replace it’s nuclear contents with a clean copy. And let’s suppose you did this throughout the body, prophylactically, perhaps even continuously.
Just to be clear, I’m not talking about using sequence data, or at least not primarily. I’m talking about detecting any sort of chromosomal aberration down to as minute as a SNP, but starting with gross NCCAs/CCAs that are detectable with spectral karyotyping and then moving down towards SNPs. Allowable degree of change would be determined empirically.
Forgetting for a moment how the nanobot achieves these feats, do you have reason to believe that this would NOT prevent cancer?
hat tip: Ace Bailey for the link to the stem cell research
Updated 03 March 2009 00:27 UTC
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Replies
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Anonymous
Hmm.. tumor suppressors might be epigenetically silenced so you would have to take this into account as well.
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Theoretically is a great idea but the devil is in the details. No matter how smart you design those nanobots they will never be perfect and the evolutionary dynamics of cancer will always find the way to exploit that. That is not to say that probably a great deal of cancers might be curable though but it might not be a silver bullet.
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Hi David -
Why must the evolutionary dynamics of cancer triumph over the potential evolutionary (and other) dynamics of the nanobots? Additionally, perhaps the nanobots will be able to confuse the cancer such that its evolutionary abilities are hampered.
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Hi Daniel, good point. As per Rafe’s comment I didn’t deduce any evolvable features on the nanobots and I am not sure that there’s anything on the definition of nanobot that implies that are naturally evolving populations. If we decided to make them so then there’s at least a couple of things to take on account:
1) We haven’t made any system as evolvable yet as the ones you can find in nature (not implying that we can’t, is just that it is not easy).
2) If you can make nanbots perfectly capable of open-ended evolution then take care that you don’t unleash a force you won’t be able to control.The message I am trying to state is not that we shouldn’t as much as that we should be very careful and aware of the challenges and potential threats.
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Hi David -
I agree, we don’t want to create a potentially dangerous evolutionary battle between cancer and the nanobots, because nobody will win. Then again, we don’t necessarily need to “win”, we may be able to continually evolve our way to a “draw”.
Regarding our current evolvable systems, well, we don’t currently have nanobots, but when we do, I think we’ll have sufficient models and computational power to simulate and program all kinds of things we can’t do now.
Also, the nanobots could work in a variety of different ways.
a) destroy the cell
b) repair the cell
c) replace the cell
d) silence the cell (gene) expression
e) subtly reprogram the cell
f) alter the functioning of the target of the mutated cellAlso, perhaps employing a variety of randomized strategies will sufficiently hamper the evolutionary capabilities of the cancer (or not, I certainly don’t know.)
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