Howard Brazee <howard DeleteThis @brazee.net> wrote:
> real-address-in-sig DeleteThis @flur.bltigibbet (Rowland McDonnell) wrote:
>
> >> Humans and apes already share something over 95% of their genes anyway.
> >
> >Humans and mice share over 95% of their genes, or so I heard.
>
> These are popular statements - but it is not obvious what meaning they
> have.
Yes it is, when you read the statements in context and find out that
what they mean is that almost all the genes in the human genome are in
the mouse genome too - something over 90% for sure.
The building block patterns - the genes - are almost all the same in
mammals; but the arrangement is different. What makes chimps more
similar to us than mice is in large part the fact that chimp genes are
arranged more like ours - and, it's got to be said, chimps do have some
genes which we have and mice don't.
But we share lots of genes with microbes too. Ever wondered why
bacteria like living in us so much? We're just like them.
Let's have a mad science fiction moment: maybe the purpose of life on
Earth is to develop a space faring species - so the bacteria can move to
another planet.
> We share molecules as well.
Indeed - all known life is based on amino acids. It's fascinating to
consider that astronomers have measured amino acids floating around in
interstellar dust clouds - all the amino acids they can detect, they
have detected. No-one knows how to get from that to life, but the
recipe probably doesn't take more than liquid water, an energy source,
and time. `Life like us' in broad terms probably does exist all over
the place.
> There are parts of our
> chromosomes which we do not yet understand which we are discovering
> are used.
Hardly anything is understood about how it all works.
> We have nerves, bones, digestive systems, skin, etc. Those parts are
> similar enough to have large parts of their genes similar as well.
That's the wrong way to look at it: the similarity in the genes is what
gives us bones of the same type as mice, built to a body plan that's
pretty much identical to ours (men like mice? Well, yes, if you compare
us to other life like slime mould or trees), and so on.
The commonality of the genetic code is why human foetuses go through a
stage which looks remarkably fishy. Our species evolved, like all
mammals, from fish. And because of that genetic code base, when the
ancestors of whales and suchlike started going back to the water, they
had everything they needed to evolve into `things a bit like fish' and
so be more adapted to the water than when they looked like bears.
> So
> let's measure them in a way that makes our point.
>
> Oil paintings of the masters and of the jokers share the same make
> ups.
Erm, what?
> A human being (or other animal) basically is a community anyway. We
> have more alien cells in us than human cells.
Alien? Hardly! All life on Earth is part of a single living community.
Bacteria are the kings of creation: most of the life on the planet,
measured by mass, is apparently bacteria. We're full of the stuff - but
it's *us*. Just as trees can't live without fungal symbiotes in its
root system, we can't live without being filled with bacteria. Bacteria
is a neccessary part of the machinery of the living planet, and while I
don't know much about it, I do know that mammalian digestion doesn't
work unless the gut's filled with bugs.
> Our brains take votes
> with some parts having bigger votes than other parts.
A lot of the `voting' is done by glands, and no-one's managed to make
any really useful measurements of `how people decide things'.
Rowland.
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