
What happens when you put evolution on replay? - Outdoorsman
https://phys.org/news/2018-02-evolution-replay.html
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chx
The title reminds of Tierra.
[https://en.wikipedia.org/wiki/Tierra_(computer_simulation)](https://en.wikipedia.org/wiki/Tierra_\(computer_simulation\))
It is astonishing. After Ray have cobbled together the best self replicating
program he could and launched the simulation, all the familiar patterns
emerged, including shorter programs than Ray could write, sexual reproduction,
parasites ... It's one of the best demonstration of evolution I am aware of
but the interpretation of it is not easy alas.

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joshuahedlund
For those arguing about the role of determinism (or lack of it) in evolution,
I just finished and highly recommend the new book Improbable Destinies by
Jonathan Losos. It covers both sides of the debate (sort of set up as "Stephen
Jay Gould" vs "Simon Conway Morris") and gets you up to speed on all the
latest fascinating stuff revealed by genome sequencing. There's a lot more to
the topic than you might expect if you haven't been following the last few
years.

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josephpmay
I feel like this article is pretty misleading in terms of the context and
significance of the research. Inserting ancestral genes in extant organisms is
a well-accepted approach to studying evolution. Evolution happens because of
environmental pressure and random luck (mutations). There's no deterministic
factor of evolution, and it's weird that the article tries to present it that
way.

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lend000
Just because evolution is governed by randomness doesn't mean you can't make
educated predictions about how an organism will evolve (at least given a set
of otherwise constant environmental pressures, which is far from assured in
the article's E Coli experiment). This is the whole premise behind convergent
evolution:
[https://en.wikipedia.org/wiki/Convergent_evolution](https://en.wikipedia.org/wiki/Convergent_evolution)

~~~
Retric
You can make a prediction about _what_ not _how._ Set things up and E Coli
will develop antibiotic immunity, repeat the experiment 100 billion times and
you might see 1+ billion different solutions. Insert fragments of a solution
and repeat the experiment and you increase the odds to get the same solution,
but the original solution space was still vast.

Consider, we say cancer mutates to disable specific genes, but not how those
genes are disabled because it's outcomes not methods that are so common.

~~~
AllegedAlec
> repeat the experiment 100 billion times and you might see 1+ billion
> different solutions

You won't, though. There has been some excellent research on this done by
amongst others Burmeister and Meyer in the Lenski group. Evolution is
'channelled' into certain solutions by its previous history and the process of
co-evolving with other species.

~~~
Retric
That simply means some solutions are more probable than others, but there is a
very long tail. Or at least as extrapolated from computer simulations.

~~~
AllegedAlec
Sure. It's still a game of chance. However, evolution is not random in the
purest sense. Evolution itself skews the distribution of the kind of mutations
you see.

For example: on of the papers by the Lenski labs show that the lambda phage
evolves a certain defense mechanism very reliably in duplicated studies,
despite it requiring several very specific mutations.

~~~
Retric
Random does not mean a uniform distribution. Toss 2 six sided dice and 2's and
12's are uncommon. But it's still a random process.

Also, saying you often get some set of mutations may be likely if subsets of
those mutations provide advantages or there is some process that makes those
mutations more likely.

~~~
AllegedAlec
> Random does not mean a uniform distribution. Toss 2 six sided dice and 2's
> and 12's are uncommon. But it's still a random process.

True, but dice don't adjust their own shape so that they're more likely to
stop at certain values.

> Also, saying you often get some set of mutations may be likely if subsets of
> those mutations provide advantages or there is some process that makes those
> mutations more likely.

Yeah, but doesn't take away from the fact that evolution is canalised into
certain options (most of the time) by its own evolutionary history.

~~~
Retric
I am not disagreeing with that. I am simply saying even if 95% of the time you
see a small set of options the other 5% get's increasingly bizarre. Start
grouping them and the last 0.001% case has just about anything.

So, sure you can specify odds, but again that's very different than saying
something is not random and thus predictable.

PS: I tend to focus on black swan events because they tend to be more
important. If you focus on the most likely outcome that becomes less important
over time. M1 - M10,000 might _each_ be happy paths, but M1 - M10,000 is is
extremely unlikely to have _all_ of them be happy paths.

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EamonnMR
If anyone is interested in arguments about winding back the clock and
replaying evolution, I highly recommended Stephen Jay Gould's "Wonderful
Life."

~~~
joshuahedlund
I also recommend the new book Improbable Destinies by Jonathan Losos, which
has a big discussion on convergent evolution and the role of "replaying the
tape" \- it refers back a lot to Gould's book "Wonderful Life" and what new
genome sequencing is revealing and how it relates to what he got right and/or
got wrong and/or how he was misunderstood.

