Re: Mutation: was (OT) Lay me down a pallet on your floor


Michael Olea wrote:
N wrote:
I can't understand this last part. I'm sorry,


I would not say that you can't, since I don't know that, but I'll agree that
you don't. Nothing personal, but I don't think you understood any of it,
not just the last part.

One clue is your use of the phrase "so called mutation", which seems to drag
in value judgements - who wants to be a mutant? But this has nothing to do
with the "mutation" I was contrasting with crossover (sexual shuffling of
existing nucleotide sequences).

so sorry again,

Lets back up a little - DNA is a string of "letters" drawn from a
4-character alphabet (nucleotides). Call the letters a, b, c, and d.
The genome (as I am using the term) of an individual is just some finite
length string made out of those letters. For example:


bbcaddacb

and its all pooh-bah but go on if you must

A "mutation" is just a change in the sequence of letters. "Single point
mutations" are: 1) changing one letter to another letter, deleting one
letter, or inserting one letter:


Substitution: bbcaddacb -> bbcadaacb
Deletion: bbcaddacb -> bbcadacb
Insertion: bbcaddacb -> bbcaddaacb

A,C,G and T

There is nothing "so called" about it - it is simply an alteration of a
sequence of nucleotides: during replication, say, the new sequence is the
same as the old sequence, an exact copy, or it isn't. The difference
between the new sequence and the old sequence, if there is any, can be
quantified as the minimum number of substitutions, insertions, and
deletions required to transform the old into the new. This number is a
"metric" - it has all the properties of "distance" in the more familiar
setting of Euclidian geometry. When you can compute the distance between a
pair of genomes you have necessarily induced both a geometry and a topology
on genome space. This is far from a sterile exercise - without it there
would be no paternity testing, no DNA "finger printing", no point to the
human genome project, no molecular clocks, no genetic phylogeny - just to
name an obvious few cases.

http://www.ensembl.org/
http://www.ornl.gov/techresources/Human
Genome/posters/chromosome/chooser.shtml

But the geometry of "genome space" is in some ways unlike the Euclidian
geometry of 3 dimensional space - in particular, there is, in general, more
than one shortest path between two points in genome space. This has both
practical and theoretical consequences. This is, in a fundamental sense,
crucial to the viability of sexual reproduction as an adaptive strategy.

At some point I lose patience: I have a lot of patience with people who know
their limits and wish to learn (e.g. Wolf, Casey), and very little with
those who pontificate on things about which they know little or nothing.
When you write:

here, drape this cold compress across your eyes...
....canapes?, seltzer?, headphones?

/*
I will repeat, genes are saucy sets, no-one knows who or what will
happen. The only thing I'll be sure about is environment for survival,
and this has little to do with 20th C. views of warped space-time,
semantic nets or planes between nodes.
*/

you are pontificating about things you clearly do not understand. Do you
want to learn new things, advance your understanding, or do you want to
pontificate like a droid?

feeling hungover lovie? hows about a good ol'fashioned
English breakfast down at a greasy-spoon cafe? ....

Anyhow, I have to figure out what to do with this damn turkey - I love to
cook, but I do things like stir-fry, chicken enchildas, and seafood pasta;
big-bird turkey is entirely outside my little window of culinary expertise.

http://www.astray.com/recipes/?search=stuffing
and you know I'm sure, if it were possible, and
we could find a table big enough for us all.....

Cheers,
Michael


HAPPY CHRISTMAS !

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