[ExI] Tim May and DNA

[William Flynn Wallace]

'DNA doesn't '"want" anything' - somebody said.

All random, eh?  Well, just why doesn't DNA produce things like one ear
smaller or some other thing that will not help or hurt survival?  No, it
has a plan.  It tries to produce better parts than what it has got, and
sometimes new parts to fit older systems, like its experiment with the
appendix.

I think DNA is smart.  I would not say aware or planning - that's
teleological.  But I just can't see it doing things randomly.

bill w

On Fri, Feb 8, 2019 at 11:30 AM Stuart LaForge <avant at sollegro.com> wrote:

>
> Quoting John Clark:
>
> > True, but there is reason to think much of the genome really is
> > nothing but parasitical junk at least from our point of view; after
> > all the entire point of Evolution is to get genes duplicated and our
> > phenotype, aka our bodies, are just a means to that end. And the
> > fact that some very commonplace looking creatures can have a huge
> > genome gives support to the idea that there must be a lot of junk in
> > genomes.
> > The human genome has about 3 billion base pairs but a
> > Mexican salamander called a Axolotl has 32 billion base pairs, the
> > marbled lungfish has 130 billion base pairs, and a humdrum looking
> > Japanese flowering plant called Paris japonica has 150 base pairs,
> > 50 times the size of the human genome. It's hard to believe that
> > little bush or the body of a  lungfish is inherently more complex
> > than a human even if its genome is.
>
> Yes, the C-value enigma still does not have a widely accepted
> solution. Even two related species in the same genus can differ wildly
> in the amount of DNA they have. Much of the controversy stems from the
> nuances of what constitutes "function" in biology.
>
> If you look at what percentage of the human genome is conserved across
> different individuals, then it is only 20% of the genome. One can
> safely assume that that 20% encodes vital functions that have been
> selected for as being necessary for survival and the other 80%, aside
> from the tiny fraction which accounts for phenotypic differences
> between individuals, could be thought of as parasitical junk.
>
> On the other hand, studies like the ENCODE project have found that if
> one defines function as binding to proteins found in the nucleus or
> being chemically modified, then 80% is functional and only 20%
> completely lacks a function.
>
> So much depends on how you define function but in the end, one does
> have a lot of extra DNA lying around in eukaryotic cells. Some
> important caveats however to the notion of junk DNA is that redundancy
> and mutation are the engines of evolutionary adaptation. The so called
> junk DNA varies widely between individuals because there is no
> selective pressure to conserve those sequences and so those sequences
> are free to silently mutate. Similarly if you have a redundant copy of
> a necessary gene, you can safely modify the copy without disrupting
> the function of the original.
>
> So perhaps junk DNA is what a programmer would call a "sandbox" where
> nature is free to experiment and innovate without disrupting crucial
> functions. I guess I am ok with the term junk DNA as long as one
> distinguishes between junk and trash. Trash is stuff you throw out
> while junk is stuff you keep because you hope to find a use for it
> someday.
>
> Stuart LaForge
>
>
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