Multicellular Life Evolves in Laboratory | Hacker News Reader

Multicellular Life Evolves in Laboratory

wired.com

93 pointsJuha24 comments

Physics might be pure, but Biology is fking amazing.

Makes me ponder my own place in the scheme of things - made up of many multicellular components, myself a component of a society, itself one of many that make up the Human species, one of many that form the ecology of this planet

One might say that it's a super computer. What's the question again?

> Is the universe actually a giant quantum computer? According to Seth Lloyd—Professor of Quantum-Mechanical Engineering at MIT and originator of the first technologically feasible design for a working quantum computer—the answer is yes

http://www.amazon.com/Programming-Universe-Quantum-Computer-...

I think it was "How many roads must a man walk down?", wasn't it?

Was this completely new, or was it some sort of latent ability that was brought out by environmental conditioning?

It was a latent ability. Some yeast already has the ability to make multi cellular colonies.

When this was first published (on June 23 - not sure why it's back in the news) there was a section of criticism saying they should have used an organism without that ability. But I don't see this section in the wired article.

For example:

http://blogs.discovermagazine.com/80beats/2011/06/23/yeast-c...

http://www.sciencenews.org/view/generic/id/331789/title/Mult...

>... not sure why it's back in the news ...

The paper [1] was just published, the first round in the news was due to the presentation of their findings, but not the publishing of any papers (as near as I can tell). Thankfully it's an open-access article.

[1] http://dx.doi.org/10.1073/pnas.1115323109

I didn't quite know how to interpret "latent ability". Reading the article, apparently yeast used to be multicellular, which is a pretty valid criticism of this experiment having meaningful results in terms of how single-celled organisms evolved into multicelluar organisms.

This comment seems to assume that evolution can only go in one direction - from simple forms of life to more complex ones. If a complex form of life evolves to become simpler and then evolves again to become more complex, then there's just as much to be learned from following a line of evolution that increases complexity.

If you look at those "simpler" forms of life you find that the genes are not gone, but rather they are disabled.

An example is Neoteny - the genes for adult forms are still there, but are unused.

That's why I don't think much of this experiment - I bet the genes for multi cellular life were already there, and just needed reactivation - which happened randomly (perhaps due to environment, or perhaps they always activate, but just for short times, and this experiment selected for those with the longest or easiest to trigger activation), but no new genes were needed.

To do this experiment properly do a DNA sequencing of the original and final forms. And I'm actually quite surprised that they didn't do that - wouldn't it be very useful to know which genes create multi cellular life? But I bet the genetic diff between them is tiny - just enough to activate genes that are already there in the starting yeast.

DNA isn't quite exactly like a program that you compile into a living organism. The conditions for its reproduction and expression are partially determined by its environment- so a shift from single celled from multi-celled life might not be able to be pinned on any particular gene or set of genes as a direct cause. You might end up with what is essentially the same sequence, with different parts now triggered by a slightly different proportion of a particular protein present within the cellular membrane.

You are absolutely correct, and it's a comment I anticipated, which is why I qualified my original statement: "meaningful results _in terms of_ how single-celled organisms evolved into multicelluar organisms". (Although in fairness, it probably gives a hint and will certainly lead to future experiments that may provide the beginnings of an answer.)

It is back on the news because: “Experimental evolution of multicellularity.” By William C. Ratcliff, R. Ford Denison, Mark Borrello, and Michael Travisano. Proceedings of the National Academy of Sciences, Jan. 17, 2012.

I know this type of Amoeba had a "slug" state that it can form - so it's possible for sure the similar genes are there already too.

http://en.wikipedia.org/wiki/Dictyostelid

Is it "muliticellular life" or "multicellular" life (i.e. group of independent yeasts actually)?

The article actually says that some cells forfeit the ability to procreate, and there is true division of labor among them.

This is wonderful. It is so simple, and takes a short enough amount of time, that it would make a fantastic lab experiment for high school students. Every day, remove the heaviest yeast and place it in a new environment and feed it. After 2 months, see that the yeast has formed into a larger organism.

If this is highly repeatable, it could have a great role for science education.

An honest question: aren't there potentially dangerous repercussions in breeding multicelular organisms like that? Could an innofensive organism become dangerous for us if it suddenly became more efficient and specialized?

Wouldn't that have happened naturally already over the thousands of years we have used yeasts?

But I don't think they'll just stick with yeasts cultures after this.

If it was so simple to do in 60 days I wonder why they don't question the several billion years.

What do you mean? Obviously, multicellular life forms did evolve in those several billion years.

From the article: "An evolutionary transition that took several billion years to occur in nature has happened in a laboratory, and it needed just 60 days."

When these transitions only took 60 days, why not take another look at the 'several billion years'? Maybe life did form much faster under certain conditions.

Ah. Sorry, I didn't quite understand you the first time.

Maybe life did form much faster under certain conditions.

You mean multicellular life here, obviously. Yeah, as the experiment shows, it probably did form fast under the right conditions. It's all about genes. If being a part of a multicellular organism allows one cell's genes to spread more rapidly, than that cell is going to have an incentive to be in a group.

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