Evolution experiment has now followed 68k generations of bacteria | Hacker News Reader

Evolution experiment has now followed 68k generations of bacteria

arstechnica.com

56 pointsxbmcuser12 comments

I think this is an enormously cool experiment on two fronts. Firstly because its a reasonably direct test of our assumptions about the basic operating model of inheritence and evolution. I could imagine critique of it on that basis, but unless somebody stumps up to fund another, this is it for that measure. So, whilst we're comfortable with a theory as a theory, this is an experiment of that theory, its operation, its behaviours over time, which permits the individual (ok every 500) generations to be analysed and compared.

Secondly, because it displays some behaviours as an experiment which I find interesting. The logistic curve of change for instance: a ramp up from slow start, and a long tail, against the cheap-to-achieve changes which maximised reproductive outcome against the constraint. The lack of an 'end point' (so yes, we as humans can continue to evolve and now we may have a reason to believe its slower than other species for a reason: we're beyond our constraint hump)

Re: "one of the 12 cultures evolved the ability to survive by eating citrate..."

Is it possible it got this trait from outside contamination, since other strains can eat citrate? Viruses can snip in foreign DNA, for example. To check, hopefully there's enough generation archives to see exactly how the ability arose. If it were a single gene "flip" rather than a set of changes, then it could be native.

Very cool. Here's more details if you want a deeper dive than what the original article had: https://en.m.wikipedia.org/wiki/E._coli_long-term_evolution_...

Thanks, that whole section on "Evolution of aerobic citrate usage in one population" is the most interesting thing I've read this year.

And by now, the bacteria have been monitoring the researchers for signs of evolution...

Anyways, what I found interesting is that one of the strains can now metabolize citrate, which as per the article E. Coli "traditionally" can not.

The article will be more accurate if evolution was not treated as a volitional choice.

Can you cite any experiment that can distinguish volitional choice from non-volitional choice (whatever that means)?

In the absence of such experiment, both options are purely speculative (by definition).

BTW, is your statement above a result of volitional choice, or non-volitional choice? How do you know? :)

This is a silly argument. You can't seriously be suggesting that the bacteria are choosing to modify their DNA in anticipation of future benefits. For sure, nothing is ever 100% absolutely known, but some things are so unlikely that we can safely assume they are not true, rather than putting a wordy disclaimer on every single "fact" that we state.

Getting back to the original point, people, including me, will say things like "this shopping cart wants to pull to the right" knowing full well that the shopping card has no desires at all. It is a useful metaphor that confuses nobody.

Modifying something for future benefits is exactly what sentient beings are doing. Yeah, bacteria are small. But small is not the same as dumb.

What are you suggesting? I am not sure you are making any sense.

If mutations in a single generation are favorable more often than would happen by chance, this would be evidence of volitional choice. But we don't see this.

I thought the article was pretty good on that front.

The passive voice is consistently used throughout ("have become hypermutators", "picked up early mutations in") and so on. The last paragraph explicitly calls out the stochastic nature of mutations and the role of selective pressures.

The only part struck me as even vaguely "volitional" is "they are each finding their own path toward the same goal of optimal fitness" , and even that is a far cry from "Giraffes evolved long necks so they could eat leaves at the tops of trees".

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