
Ancient Viruses Buried in DNA - grzm
https://www.nytimes.com/2017/10/04/science/ancient-viruses-dna-genome.html?action=click&pgtype=Homepage&version=Moth-Visible&moduleDetail=inside-nyt-region-5&module=inside-nyt-region&region=inside-nyt-region&WT.nav=inside-nyt-region&_r=0
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wyldfire
Credit H.G. Wells:

> By the toll of a billion deaths man has bought his birthright of the earth,
> and it is his against all comers; it would still be his were the Martians
> ten times as mighty as they are. For neither do men live nor die in vain.

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whipoodle
Other species have chalked up a lot more deaths than that.

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dymk
But they don’t write about it

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typetehcodez
Read 'Darwin's Radio' by Greg Bear.

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dmach
First heard of this from Frank Ryans book Virolution. It explains a lot of
what had been termed junk DNA previously.

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otakucode
I've not heard of that book before but will have to check it out. Did it
happen to mention any of the experimental research done showing that removal
of 'junk DNA' makes organisms (microorganisms anyway) less capable of adapting
to environmental change? As I remember it, some researchers took a bacteria
(probably e. coli, that's usually the easiest to do this sort of thing with
but I'm not certain) and separated out two populations. In one they let it be,
and in the other they stripped out all 'junk' DNA that didn't play a role in
protein synthesis. Then they introduced harsh conditions to both (I think
something like high acidity or low availability of food or something like
that) and while the 'junky' population adapted relatively quickly, the 'pure'
population quickly died off and wasn't able to gain beneficial mutations
quickly enough to survive.

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21
And there is another line of thought.

Bacteria's pay dearly for each extra bit of DNA they carry, since the energy
cost of DNA replication is linear with respect to the length.

Bacteria's with less DNA can replicate more quickly and thus outcompete other
bacterias.

The fact that after so many generations they still carry that "junk" which
they pay for suggests it really is useful in one way or another.

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Geee
So can genes transfer between species via viruses? Is that why our features
are similar to pigs?

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patall
As has been answered before, we know for a fact that gene transfer exists
between species, we just do not know for sure how it happens (as it is
certainly a very rare event). Potential candidates are extracellular RNAs,
intracellular bacteria as vehicle and last but not least transfer via
virusses.

On the other hand, our features are not particular similar to pigs, its just
that pigs are similar sized mamalian omnivors (ergo similar inner organs) and
can be bred well.

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saalweachter
I suspect a close examination of the pig's genome would also be a remarkably
multifaceted demonstration of the DNA evidence for evolution.

Two minute introduction: life is largely built out of proteins, which are
chains of amino acids (small organic molecules) which "fold" into interesting
shapes and interact with each other in interesting ways. Our DNA is a set of
blueprints for making a suite of proteins that builds us.

One of the curiosities in our DNA is that multiple sequences can code for the
same amino acid in a protein. It doesn't matter how it's coded in your DNA,
the protein still functions the same way. So one piece of evidence in favor of
evolution is that most organisms share a common DNA sequence for common
proteins, even though there are potentially millions (or more!) of different
sequences which would code for the same protein.

So if humans and pigs have evolved any of the same proteins since they
diverged millions of years ago, you should also expect them to be coded for in
"more different" ways than if they were evolved in a common ancestor.

(You wouldn't expect the coding for the proteins to be completely different,
since they probably evolved from a protein shared by the common ancestors.)

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ne9xt
Thank you for that explanation!

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eighthnate
I thought these foreign viruses become part of our DNA which we pass down from
generation to generation.

It isn't buried in our dna rather inserted into it and become part of our dna.

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iaw
I read a previous article years ago that argued certain traits (mental
illness, risk-taking, etc.) could be the result of viruses that successfully
joined the human genome via the reproductive organs.

This area of study could end up pretty interesting.

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ComputerGuru
I don’t think it makes a difference though if the genetic changes happen via
happenstance (cosmic radiation, etc) or via infiltration due to viruses, etc,
does it? Isn’t it all one and the same to evolution?

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PoachedSausage
I don't think it is the same. Virus DNA has the purpose of making more Virus,
it has function and structure, not just overwriting with randomness.

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petethepig
DNA is the world's oldest blockchain

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pazimzadeh
DNA is the opposite of immutable

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truxus
Does your DNA change day to day?

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mikeash
According to Wikipedia, "In human cells, both normal metabolic activities and
environmental factors such as radiation can cause DNA damage, resulting in as
many as 1 million individual molecular lesions per cell per day."

There are mechanisms to repair this damage, but they don't always work.
Sometimes the result is cancer.

