[extropy-chat] BIO: Stem Cell Genes

[Robert J. Bradbury]

On Tue, 23 Dec 2003, Damien Broderick wrote:

> How do you know when you find it? I'd have thought: take 100 stem cells,
> then take a majority vote at each allele locus (if that's feasible), then
> compile the most popular choices.

Majority rule might be interesting within an individual.  The problem is
that there may be epigenetic phenomena (there is now an epigenomic project)
caused by genomic modifications within individual cells (causing 1 stem cell
not to be equal to another stem cell).  In addition actual gene expression
patterns may be influenced by circulating hormone levels which are in turn
influenced by cells elsewhere.

Ideally you would like to sequence the genomes of each stem cell and find
the one most similar (having suffered the least damage probably) to that
you were born with.  Thats probably what you want to run with.  However,
as we understand the program better it may be that we discover what
a more idealized genome should be -- in which case one might want to
pick the stem cell closest to that.  Eventually one would do gene
therapies on the stem cell to drive it closer to the ideal even
though that might be less like you.  This gets tricky because one
would want to take it right up to the edge of where your immune
system starts rejecting the engineered stem cells as foreign.

> Google:
> No pages were found containing "chromallocytes".

Sorry, I'll send you the reference off-list since it isn't published
yet (maybe this year if we are lucky).  If you read between the lines
of Nanomedicine VI and a couple of Robert's papers it clear that
you can do chromosome extraction and replacement.  I've called
this "nuclear abortion" in several talks much to the displeasure
of Robert F.

Robert