×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Multicellular Life Evolves In Months, In a Lab

Soulskill posted more than 2 years ago | from the selecting-for-extroverted-cells dept.

Science 285

ananyo writes "The origin of multicellular life, one of the most important developments in Earth's history, could have occurred with surprising speed, U.S. researchers have shown. In the lab, a single-celled yeast (Saccharomyces cerevisiae) took less than 60 days to evolve into many-celled clusters that behaved as individuals. The clusters even developed a primitive division of labor, with some cells dying so that others could grow and reproduce. Multicellular life has evolved independently at least 25 times, but these transitions are so ancient that they have been hard to study. The researchers wanted to see if they could evolve multicellularity in a single-celled organism, using gravity as the selective pressure. In a tube of liquid, clusters of yeast cells settle at the bottom more quickly than single cells. By culturing only the cells that sank, they selected for those that stick together. After many rounds of selection over 60 days, the yeast had evolved into 'snowflakes' comprising dozens of cells."

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered

285 comments

Organized trolling campaign on Slashdot (-1, Troll)

Anonymous Coward | more than 2 years ago | (#38733928)

GreatBunzinni [slashdot.org] has been posting anonymous accusations [slashdot.org] listing a whole bunch of Slashdot accounts as being part of a marketing campaign for Microsoft, without any evidence. GreatBunzinni has accidentally outed himself [slashdot.org] as this anonymous poster. Half the accounts he attacks don't even post pro-Microsoft rhetoric. The one thing they appear to have in common is that they have been critical of Google in the past. GreatBunzinni has been using multiple accounts to post these "shill" accusations, such as Galestar [slashdot.org], NicknameOne [slashdot.org], and flurp [slashdot.org].

That's not the problem. The problem is that moderators gave him +5 Informative and are now modding down the accused, even for legitimate posts. Metamoderation is supposed to address this by filtering out the bad moderators, but clearly it's not working.

This "shill" crap that has been flying around lately has to stop. It's restricting a variety of viewpoints from participating on the site and creating an echo chamber.

Re:Organized trolling campaign on Slashdot (-1, Offtopic)

AngryDeuce (2205124) | more than 2 years ago | (#38734010)

Dude, whoever you are, please stop. I'd rather read a stupid frist psot comment than this crap on every fucking article.

Re:Organized trolling campaign on Slashdot (0, Offtopic)

Anonymous Coward | more than 2 years ago | (#38734092)

Holy crap, your post history is almost entirely +5 karma whoring. I've never seen so many pandering, populist +5 comments.

Re:Organized trolling campaign on Slashdot (-1)

Anonymous Coward | more than 2 years ago | (#38734062)

P.S.: Disregard that, I suck cocks.

Re:Organized trolling campaign on Slashdot (0, Offtopic)

another_twilight (585366) | more than 2 years ago | (#38734150)

I had no idea who GreatBunzinni was until your crapflood.

I see no evidence in your posts of GreatBunzinni using multiple accounts to shill. I see a possible AC post. I see someone questioning bonch.
You on the other hand are a spammy bastard who is haunting Slashdot and amassing a GNAA-worthy number of FPs. One has to wonder whether you are paid for your attentiveness.

I recognise some of the names on GreatBunzinni's list and thought they sounded a little 'shill'. Now this. It adds weight to my suspicions.

If you are one of the aggrieved, respond to posts where they out you. Logged in. Maybe the GreatBunzini has included some names they shouldn't have. Until then, _your_ crusade has just confirmed the GreatBunzini's accusations, as far as I am concerned. Well done.

With apologies for the offtopicness of this post.

Re:Organized trolling campaign on Slashdot (-1)

Anonymous Coward | more than 2 years ago | (#38734236)

You must be the most easily led person on the planet. GreatBunzinni's list is nothing more than a bunch of people he doesn't like followed by a website link. If that's all it takes to convince you of something, then you're what Stalin would have described as a "useful idiot."

Re:Organized trolling campaign on Slashdot (-1)

Anonymous Coward | more than 2 years ago | (#38734300)

And were I using the list, alone, you may even be right.

Do you even read the posts you reply to, or just skim the highlights? I said that I had already noted a pattern to some of the mentioned people's posts. Had I come across the list on my own I would have thought nothing more than that someone else thought the same way I did or noticed the same patterns and was maybe taking it a bit too far. Then I would have dismissed it and thought no more about it.

But this? These first posts? The attentive responses?

Nah. Someone's been stung. Methinks the lady doth protest too much, etc.

Call me some more names. That is sure to convince me.

Re:Organized trolling campaign on Slashdot (0)

Anonymous Coward | more than 2 years ago | (#38734340)

So you believe that a bunch of people who share the same opinions about Google means that they're part of a "rapid response team" hired by Microsoft? Really?

Do you read the posts you're replying to?

Re:Organized trolling campaign on Slashdot (-1)

Anonymous Coward | more than 2 years ago | (#38734402)

How many ways can I explain this?

So you believe that a bunch of people who share the same opinions about Google means that they're part of a "rapid response team" hired by Microsoft

On it's own, no. As I said.

But ACs flooding FPs with their own conspiracy shows a level of ... concern that verges on the professional. ACs mining comment history to make snide comments about karma whoring and resorting to name calling shines a whole new light on this. ACs refusing to sign in so that we might know who is really concerned is just ... well, you're stretching plausible deniability a little, don't you think?

Oh, I doubt that list is completely accurate - these things seldom are. Someone with a similar opinion and/or style usually gets caught up. But it sure struck someone's nerve, didn't it?

Your manner and arguments have completely convinced me. The name calling is a nice touch. I am shamed and defeated. Bravo.

Re:Organized trolling campaign on Slashdot (0)

Anonymous Coward | more than 2 years ago | (#38734464)

No nerve was struck. I just found it shocking that someone would actually believe a random list of names and a URL, and then continue to justify that belief, complete with nutty implications that I'm getting paid to post (uh, does that mean you are too?). I suggest going back to karma whoring for more +5s.

Re:Organized trolling campaign on Slashdot (0)

Anonymous Coward | more than 2 years ago | (#38734816)

No nerve was struck.

Of course there wasn't.

I suggest going back to karma whoring for more +5s.

You used that insult against AngryDeuce. Your material is getting stale. Or is the script that shallow?

Re:Organized trolling campaign on Slashdot (0, Troll)

larry bagina (561269) | more than 2 years ago | (#38734362)

I have a theory. It's not pro-microsoft shills or rogue google Kenya/India employees or whatever troll conspiracy shit you think it is.

It's actually Kevin Rose.

The digg guy.

They fucked the pooch on their last redesign. So now they're trying to turn slashdot into a cesspool to bring back eyeballs. They also used their elite hacking skills to update the slash codebase with all the gay facebook/twitter/google+ buttons.

Not so sure about this. (5, Informative)

Anonymous Coward | more than 2 years ago | (#38733946)

This is likely just re-emergence of previously evolved and currently dormant behavior.

Re:Not so sure about this. (-1)

kaellinn18 (707759) | more than 2 years ago | (#38733984)

This. I'd mod informative if I could.

Re:Not so sure about this. (4, Funny)

syousef (465911) | more than 2 years ago | (#38734042)

This. I'd mod informative if I could.

Slashdot moderation simply hasn't evolved to the point where you can.

Re:Not so sure about this. (3, Funny)

moderatorrater (1095745) | more than 2 years ago | (#38734476)

It's +5 informative now. Apparently our community acts as a group.

Re:Not so sure about this. (3, Funny)

cyachallenge (2521604) | more than 2 years ago | (#38734512)

Apparently the group has become self aware!

Re:Not so sure about this. (4, Funny)

syousef (465911) | more than 2 years ago | (#38734704)

Apparently the group has become self aware!

Nuke from orbit. It's the only way to be sure!

Re:Not so sure about this. (1)

Anonymous Coward | more than 2 years ago | (#38735284)

It has now become meta-self aware, or even meta-self meta-aware! Or is it meta-meta-aware?

WE ARE SELF AWARE AND WE KNOW ABOUT IT!

Re:Not so sure about this. (5, Informative)

Anonymous Coward | more than 2 years ago | (#38734044)

Also mentioned in tfa. The scientist says that he plans to do an experiment with organisms without multicellular ancestors.

Yes - sounds like "grant time" (5, Insightful)

Moblaster (521614) | more than 2 years ago | (#38734158)

I suspect it's not "evolution" at all, but subtly bad science (i.e. a scientist gunning for more grant money). DNA can express in many ways given varying environmental conditions, without the mutations that characterize true evolution -- and artificially forcing genetic drift by selecting for the bottom-clumpers is certainly VERY DIFFERENT from having gravity serve as the "selection pressure."

It's well known DNA can express in many different ways without true evolution. We've come a long way from the theory of Lamarckian evolutionary theory (evolution of acquired characteristics). One is example: exons, which can express differently across generations based on environmental conditions-- without actual change to the DNA.

I'm thinking this great discovery will get pounded upon by other biologists pretty quickly -- and put in its proper place as an interesting science experiment that really does not advance the field much if at all. INTERESTING evolution would be a group of mutations that lead to a multicellular outcome. That's NOT what these guys 1) demonstrated happened (multicellular DNA base-pair-causing mutations) or 2) proved was the actual genetic cause at the molecular-biology level.

Re:Yes - sounds like "grant time" (-1)

Anonymous Coward | more than 2 years ago | (#38734260)

I suspect it's not "evolution" at all, but subtly bad science (i.e. a scientist gunning for more grant money). DNA can express in many ways given varying environmental conditions, without the mutations that characterize true evolution -- and artificially forcing genetic drift by selecting for the bottom-clumpers is certainly VERY DIFFERENT from having gravity serve as the "selection pressure."

Ummm... 10 yeast cells clumped together have more mass than 1 yeast cell. Therefore they sink to the bottom of a tube. You can use caps and call it genetic drift and exclaim that it's VERY DIFFERENT, but that doesn't mean you have two brain cells clumping together.

Genetic drift connotes genetically identical organisms separated by vast space and time... not ordinary yeast in a test-tube. You wouldn't expect genetic drift in a test-tube of yeast. In fact, that would be quite a finding of its own right.

In short, you're an idiot, and you should give me your 6-digit slashdot ID.

Re:Yes - sounds like "grant time" (5, Informative)

airuck (300354) | more than 2 years ago | (#38734392)

10 yeast cells clumped together have more mass than 1 yeast cell. Therefore they sink to the bottom of a tube.

Bzzt. Please review the difference between mass and density and the relationship between density and buoyancy.

so dna mutation over generation is not enough for (1, Troll)

unity100 (970058) | more than 2 years ago | (#38734312)

you.

http://www.newscientist.com/article/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.html [newscientist.com]

and you need bacteria not only to evolve in dna, but also develop into a multicellular organism. in your lifetime.

please.

Re:so dna mutation over generation is not enough f (1)

tibit (1762298) | more than 2 years ago | (#38734452)

This is quite informative. The simplistic experiment in the TFA seems to be just that: simplistic. IOW - bad science.

Re:Yes - sounds like "grant time" (5, Informative)

Eskarel (565631) | more than 2 years ago | (#38734430)

The summary is true, but ultimately misleading.

This is evolution, and it did happen in months. What it doesn't account for is getting the clumping gene in the first place, and that the likelihood of getting selection pressures as extreme as the ones in the lab is fairly low.

They've proven that yeast has the capacity to evolve in this way given the right selection pressures, which is interesting. With additional research they may be able to prove that many other single celled life forms have the same capacity, from which we may extrapolate that the gene responsible for this behavior either occurred very early or is a relatively minor mutation.

The "more quickly than we believed" part is probably bogus. They applied extreme selection pressures to this particular colony of yeast and so they got an extreme time scale result the same would happen in any species if you extrapolated for the length of a given generation. You could do the same thing to humans for some arbitrary characteristic.

Re:Yes - sounds like "grant time" (4, Informative)

koekepeer (197127) | more than 2 years ago | (#38734556)

IIRC from the times when I used yeast in my PhD research, wild type (that means: not mutated) S. cerevisiae clumps in advanced stationary phase (end of growth curve, nutritional deprivation). Such circumstances happen more often that not in the real life of S. cerevisae: just imagine that in nature it cannot walk to the nearest grapevine and say 'hey lets do some sugar fermentation here'... no it depends on being able to survive in times of drought. ne way it does that is through forming spores, another way of temporarily surviving could be this kind of 'clumping'. So, the 'clumping gene' is already there, it is just expressed in certain circumstances, circumstances easily simulated in a lab situation.

In my mind the argument would revolve around self-organisation versus (old, dormant) organisational information still present in the S. cerevisae genome. I'm bummed I cannot access the original article at the PNAS site, else I could comment on that in a bit more detail.

Re:Yes - sounds like "grant time" (5, Insightful)

robotkid (681905) | more than 2 years ago | (#38735134)

I suspect it's not "evolution" at all, but subtly bad science (i.e. a scientist gunning for more grant money). DNA can express in many ways given varying environmental conditions, without the mutations that characterize true evolution -- and artificially forcing genetic drift by selecting for the bottom-clumpers is certainly VERY DIFFERENT from having gravity serve as the "selection pressure."

It's well known DNA can express in many different ways without true evolution. We've come a long way from the theory of Lamarckian evolutionary theory (evolution of acquired characteristics). One is example: exons, which can express differently across generations based on environmental conditions-- without actual change to the DNA.

I'm thinking this great discovery will get pounded upon by other biologists pretty quickly -- and put in its proper place as an interesting science experiment that really does not advance the field much if at all. INTERESTING evolution would be a group of mutations that lead to a multicellular outcome. That's NOT what these guys 1) demonstrated happened (multicellular DNA base-pair-causing mutations) or 2) proved was the actual genetic cause at the molecular-biology level.

IAAMBP (I am a molecular biophysicist) and I actually just finished discussing this article at work before seeing it on /. The parent post is an odd mix of insightful comments and flamebait so I'll respond to the former. BTW the actual research article itself is free for everyone to read, thanks to the authors shelling out an extra 1K$ to allow public access. I'll link it below:

http://www.pnas.org/content/early/2012/01/10/1115323109.full.pdf+html [pnas.org]

If you would prefer having to pay 10-30$ for the privilege of reading what your tax dollars already paid for instead of this commie "open access" stuff, please call your congressman and tell him/her to support HR bill 3699.

To contextualize this work: the path that led from single-celled eukaryotes to multicellular organisms is one of those $64,000 questions in evolutionary biology, that weird crossover from outright competition to coordinated teamwork. The advantages of being multicellular really pay off for big, complex organisms, but why on earth would it have been advantageous for a small group of a few dozen cells? This paper does not answer the question by any stretch, but it does provide a few interesting, unexpected clues. Most groups asking this question focus on Volvocine algae, which evolved multicellularity so recently such that you can compare them side by side with their nearly identical single-celled cousins in the very same pond. But these are not the most convenient organisms to work with; they have a very complicated life cycle, and have a monster-sized genome for their diminutive size (~140 million bases) and doing genetics on such beasties is still quite difficult and tedious.

Yeast, on the other hand, are really easy to work with and are actually pretty boring in most respects; ~12 million base pairs which have all been sequenced many times over. You can actually custom order them with any gene you want deleted just to see what happens, it's that well characterized. So the observation that artificially selecting for clusters in boring yeast leads to weird snowflake-shape colonies with something that resembles "programmed cell death" in higher organisms is completely unexpected an novel. "Programmed cell death" literally means that the colony has found a way to promote what's good for the colony over what's good for the individual, even though these are only 60 days removed from being a pretty ordinary yeast.

Is this how it happened billions of years ago? Probably not, this is just boring yeast after all, and I can't think of a scenario where sinking to the bottom is a life-or-death advantage. In the case of the algae, it would in fact be suicidal to sink beyond where the light can reach you. Could the finding that "apoptosis" can spontaneously arise in clumping cells be one of the things that had to happen In Real Life? Who knows. Maybe. But it was certainly not expected, hence the paper.

sounds like "grant time"

Unless you an independently wealthy, it is always grant time in academia. The NSF (which funded this study) has 2 grant cycles a year, the NIH has 3. So every experiment that works is either going to be in a progress report for the current grant or preliminary data for the next one. For a tenured professor, between 30-70% of your stated salary is dependent on your ability to raise it from grants (variability depends on how much you have to teach and how wealthy your department is). For a non-tenure-track professor, it could be 100%. So yes, any result of even the smallest significance will always be presented in the flashiest, slickest way possible in the most prestigious journal possible without actually crossing the line into outright misrepresentation of what happened. That's just how it is, your tax dollars at work enforcing artificial selection of the flashiest science that generates the most buzz.

and artificially forcing genetic drift by selecting for the bottom-clumpers is certainly VERY DIFFERENT from having gravity serve as the "selection pressure."

No, genetic drift is what happens when mutations change in frequency in a population entirely due to random sampling. Artificially selecting for bottom-clumpers over many generations is not random and is in fact the very definition of an (artificial) selection pressure. A very valid criticism, however, is that the authors do not even speculate how this selection pressure may in any way resemble one that exists naturally. Is there some environment where sinkers get more nutrients and floaters get eaten or killed? If not, then this is just a curious "what if" experiment and not at all a real candidate for how multicellular organisms came about primordially. Interestingly, they mention prior work by competitors in which the selection pressure applied was a small predator species whose mouth could only eat a single-celled organism, and the prey adapted by forming small clusters of 8 cells too big to fit in the predators mouth.

INTERESTING evolution would be a group of mutations that lead to a multicellular outcome.

Yes. That's exactly why they did that. You are right to question how relevant their answer is, however.

One is example: exons, which can express differently across generations based on environmental conditions-- without actual change to the DNA.

Yes, complex organisms have alternative splicing, but this is yeast, which has almost no introns. Something like 90% of yeast genes have zero introns, the other 10% maybe one small intron so not that many ways to splice and dice. Humans, by comparison, have an average of 10-11 introns/exons in any particular gene.

1) That's NOT what these guys demonstrated happened (multicellular DNA base-pair-causing mutations)

They did demonstrate an inheritable trait that responds to an artificial selection pressure. Occam's razor said it was due to mutations and not some weird epi-genetic x-factor we haven't discovered yet.

or 2) proved was the actual genetic cause at the molecular-biology level.

You said it yourself, it's "grant time". I'm betting they chose yeast because now they can get the interesting ones sequenced for a few thousand each, which is completely feasible even with a very modest grant compared to what it would cost for algae (or anything that isn't yeast or e. coli really).

Re:Not so sure about this. (5, Informative)

Anonymous Coward | more than 2 years ago | (#38734208)

This was on RichardDawkins.net back in June, and in the version of the article linked there, there were these telling paragraphs:

Sceptics, however, point out that many yeast strains naturally form colonies, and that their ancestors were multicellular tens or hundreds of millions of years ago. As a result, they may have retained some evolved mechanisms for cell adhesion and programmed cell death, effectively stacking the deck in favour of Ratcliff's experiment.

"I bet that yeast, having once been multicellular, never lost it completely," says Neil Blackstone, an evolutionary biologist at Northern Illinois University in DeKalb. "I don't think if you took something that had never been multicellular you would get it so quickly."

Re:Not so sure about this. (1)

wvmarle (1070040) | more than 2 years ago | (#38735066)

It will definitely take longer - how long is anyone's guess. Nevertheless it'd be an interesting experiment.

Now a variation. Evolution involves random mutations: most don't do much if anything, others are lethal, and some will give a small advantage and giving those individuals an edge. These random mutations, mostly DNA copying errors, are thought to be caused by a.o. radiation. We are constantly bombarded by a low dose of cosmic radiation, and I would expect that is a major source of such errors. An impact by a cosmic ray at just the right moment and the wrong amino acid is built into the DNA.

Would it be possible to speed up such an experiment by adding a small dose of radiation in the mix? Maybe something like 10 times background radiation or so, or whatever is considered safe for life - after all you don't want to kill off the experiment right away. Such radiation levels should increase the number of mutations, putting more randomness in the mix, and a higher chance to change the behaviour of the organism.

Re:Not so sure about this. (0)

Anonymous Coward | more than 2 years ago | (#38735532)

^ This is the first thing I thought upon reading the brief above. It strikes me as somewhat extraordinary that the scientists in question hadn't thought of it. Well, I expect they had, it's just that the press release associated with all science these days seems to be embedded in buckets of unmitigated twaddle.

I've always wondered... (5, Insightful)

Beeftopia (1846720) | more than 2 years ago | (#38733986)

Do the mechanisms which originally created life still occur? Or is "The Genesis Event" so rare that it was a one-time occurrence billions of years ago?

Genesis (5, Funny)

sakdoctor (1087155) | more than 2 years ago | (#38734054)

God still holds the copyright for the original genesis event. It should have entered the public domain, but the copyright just keeps getting extended, and extended for billions of years. God keeps raking in the royalties and has no incentive to create new works, which is why you haven't heard anything from him lately.

Re:Genesis (1)

gtb (2555306) | more than 2 years ago | (#38734854)

In further news, God says 'Meh, I did it in six days. I've got better things to do now' and settles back on the couch with Christoper Hitchens to have an all-night session watching season 2 of South Park that they downloaded from an illegal torrent.

Re:Genesis (0)

Anonymous Coward | more than 2 years ago | (#38735120)

Although God's written will says that the meek shall inherit the (copyright to) the Earth.

Re:I've always wondered... (5, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#38734076)

That's a big question! We currently believe that the circumstances that created life were pretty harsh in some respects and extremely mild in others. There are a number of different ideas floating around [wikipedia.org], including the proverbial primordial soup, clouds of space dust (panspermia), and a boiling puddle of fat. Most likely, the conditions that were on Earth billions of years ago (a hot boiling hell with a mostly hydrogen atmosphere, amongst other things) contributed substantially to the factors that led to life's rise.

Re:I've always wondered... (5, Interesting)

tchuladdiass (174342) | more than 2 years ago | (#38734154)

Now a related question -- is there any evidence (for or against) that life originated more than once on earth? Is the prevailing theory that a single reproducing organism came into being, from which all others were derived, or is it more likely that multiple instances of life happened over the course of time, and they all happen to take the same form? If this is the case, then it lends credence to life existing elsewhere in the universe, with much similarity to what we know. However, if it is unlikely for more than one independent instance of life to be similar, then we should be observing various non-related life types here on earth (i.e., some carbon based, some silicon based, etc).

Re:I've always wondered... (5, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#38734194)

This has indeed been pondered! We're pretty sure that all life that presently exists all comes from one root, however. If there ever were alternative life-starting events, they didn't survive. The reason for this is that all extant organisms share a number of completely arbitrary decisions called chirality [wikipedia.org] (if you know any physics, that's left-handed vs. right-handed molecular symmetry.) Chirality is completely random in the chemical reactions that produce amino acids and nucleotides, but absolutely fixed, in the same way, in every living organism we've studied. A number of environmental tests have been conducted specifically to look for organisms of contrary chirality, but we haven't found anything yet.

Re:I've always wondered... (1)

DigiShaman (671371) | more than 2 years ago | (#38734442)

Wow! If that's the case, we may very well be all alone in the universe. A glitch of epic chance that should never have happened, but statistically would have sooner or later anyways. Earth just happened to be the place for this event to occur on.

I really hope that's not the case. I sure would like to believe life is a common theme among planets with oceans of water.

Re:I've always wondered... (3, Interesting)

Samantha Wright (1324923) | more than 2 years ago | (#38734642)

As would we all. Fortunately, the Fermi paradox ("why haven't we stumbled onto aliens yet if they're out there?"), one of the biggest puzzles in such questions, is easily answered with "because they're probably just getting started" due to the nature of star formation.

Re:I've always wondered... (3, Insightful)

dwye (1127395) | more than 2 years ago | (#38735108)

More likely, it occurred once, and the first species ate the primordial soup until conditions (mainly nutrient density, I expect) dropped below the level that allowed abiogenesis to repeat. All that is required is that the expected time between abiogenesis events is longer than the time for first life to reproduce and spread throughout the world (or at least that part where the event could reoccur), and you have just one life event per planet (at least for most planets - statistically at least a few times the events must occur too frequently for only one type to dominate).

Re:I've always wondered... (1)

wvmarle (1070040) | more than 2 years ago | (#38734580)

This has indeed been pondered! We're pretty sure that all life that presently exists all comes from one root, however.

That doesn't surprise me in the least. There are so many similarities between various life forms it almost has to have a single root. With that I'm thinking of e.g. DNA: all life forms use the same four aminoacids and the same basic mechanisms for handling DNA, with minor variations like viruses that use RNA iirc. It's been a while since I had my biology lessons.

Also the basic structure of cells is pretty much the same throughout all life forms. All cells have their mitochondria, their core, etc., often using the same proteins even. All those things already point to a single ancestor. Recently here on /. there were reports of extremophiles using arsenic in their DNA, that to me are still life forms very similar to the rest - still using DNA and proteins etc. They just adapted to live in a different environment, something that we call extreme, but what they would call home sweet home.

Re:I've always wondered... (4, Insightful)

Samantha Wright (1324923) | more than 2 years ago | (#38734726)

A few clarifications, and things you might find neat:

1. The nucleus and mitochondria only appear in more complex organisms (eukaryotes.) Simpler ones (prokaryotes: bacteria and archaeons) are just bags with DNA in them. Mitochondria and chloroplasts (and their less well-known cousins, chromoplasts and amyloplasts) actually started out as different kinds of bacteria and just got absorbed into a cell one day. They even have their own DNA, ribosomes, and reproductive cycle.
2. No two species have exactly the same proteins, but their sequences are similar enough that we can infer homology (relatedness) over great distances; often billions of years of separation. That being said, there are some species so isolated and so remote (because all of their relatives have died off) that we have trouble proving homology for—but these species still do more or less the same functions with similarly-shaped proteins.
3. The arsenic-using extremophile was more like arsenic-tolerant. Normally, organisms die when they take up arsenic because it replaces phosphorus with a heavier nucleus that has different binding affinities. However, the organism those researchers discovered was capable of replacing at least some of its phosphorus with arsenic without dying. But yeah, your point is correct! :)
4. It's widely believed now (in an idea called the RNA World hypothesis) that DNA and proteins were invented later. The original "life" was probably a self-replicating RNA molecule. RNA can perform both catalytic functions (like proteins) and information storage functions (like DNA), it's just not as good at them. It still performs many of these functions in the modern cell as well—almost the entire ribosome (the protein making machine) is made out of RNA, and there's a large class of so-called "ribozymes" that can cut and modify other molecules.

Re:I've always wondered... (1)

wvmarle (1070040) | more than 2 years ago | (#38734940)

The more you learn about it, the more complex life becomes!

Mitochondria and chloroplasts (and their less well-known cousins, chromoplasts and amyloplasts) actually started out as different kinds of bacteria and just got absorbed into a cell one day. They even have their own DNA, ribosomes, and reproductive cycle.

I am familiar with mitochondria having their own set of DNA, but that's pretty much how far my knowledge in the subject goes. And that this DNA is not shared through sexual reproduction: in case of human reproduction the mitochondrial DNA is exclusively the mother's, as sperm cells don't have any. But I've never heard about them having their own reproduction cycle etc - it seems like we could call mitochondria a separate life form, living in symbioses with us.

Re:I've always wondered... (4, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#38734980)

Yep. It's called endosymbiotic theory. For a while it was just a crazy idea, but we're pretty sure we know exactly what kind of bacterium it came from (purple and green sulphur bacteria for mitochondria and chloroplasts, respectively.) Another name for it might be "yet another blatant dagger in the back of intelligent design," but genomics is a treasure trove of those on any day.

Re:I've always wondered... (1)

wvmarle (1070040) | more than 2 years ago | (#38735006)

I'm sure those intelligent design people will use this to support their theory, it's surely easier than to explain fossils etc in a young-earth theory: how can such a complex design come into being without a highly intelligent designer creating it?

Re:I've always wondered... (4, Interesting)

robotkid (681905) | more than 2 years ago | (#38735542)

This has indeed been pondered! We're pretty sure that all life that presently exists all comes from one root, however. If there ever were alternative life-starting events, they didn't survive. The reason for this is that all extant organisms share a number of completely arbitrary decisions called chirality [wikipedia.org] (if you know any physics, that's left-handed vs. right-handed molecular symmetry.) Chirality is completely random in the chemical reactions that produce amino acids and nucleotides, but absolutely fixed, in the same way, in every living organism we've studied. A number of environmental tests have been conducted specifically to look for organisms of contrary chirality, but we haven't found anything yet.

There are two points here. As for the single root of life, I saw Carl Woese give a talk on this - see timely PNAS perspective here if you have institutional access: http://www.pnas.org/content/early/2012/01/13/1120749109.short?rss=1 [pnas.org]
  (he's a giant in evolutionary biology and the one who proved archaea were a separate lineage using ribosomal RNA sequences, thus redefining our understanding of microbiology, so I'm inclined to give large weight to his views)

His view was that some events almost certainly happened to one unique organism, you can do the backwards projection on the endosymbiosis of mitochondria and a very distinct genetic profile emerges from multiple, independent lines of evidence. But when you try and project all the way back to the LUCA (last universal common ancestor of all three kingdoms) the uncertainty becomes so large and some of the contradictions so severe that it is in fact best explained by groups of highly similar (but not identical) universal ancestors over a window of time, not just literally one unique genome at a specific point in time. So he thinks that the "base" of the tree of life ends up being more like a collection of small shrubbery or bushes instead of a singular point of origin. Carrying that thought a bit further, if there were indeed multiple bushes of life at the start it seems probable there were also other bushes that completely vanished without a trace (no fossil record possible).

As for the universal chirality, that speaks to the origin of self-replicating macromolecules that would have preceeded the last universal common ancestor by quite a spell, so we can only speculate what happened based on our knowledge of organic chemistry. NASA funds some rather creative chemists to think about this question to help define what life might be like elsewhere, and last time I saw one of them speak they seemed to be of the opinion that it was probably just a random chance that gave us one hand and not the other and that there were pools of similar chemical species being selectively concentrated by some sort of clay catalyst. But that means it could have occurred multiple times and only one pool resulted in a proto-cell, or multiple proto-cells arose and the rest died off, or maybe all steps really did only happen once, there's absolutely no projection or record to build upon except geological models of what the earth might have been like then.

Re:I've always wondered... (1)

mrchaotica (681592) | more than 2 years ago | (#38734248)

My wild, completely uninformed guess is that life originated multiple times, and each subsequent new instance got immediately eaten by the (by then more evolved) first one.

Re:I've always wondered... (1)

Beeftopia (1846720) | more than 2 years ago | (#38734530)

My wild, completely uninformed guess is that life originated multiple times, and each subsequent new instance got immediately eaten by the (by then more evolved) first one.

And perhaps with the universe occasionally hurling a massive rock at the earth, destroying much of the more evolved life on it in an epochal extinction event [wikipedia.org], allowing life to evolve in yet another direction. The impact point [wikipedia.org] may have had some of the attributes of the ancient earth.

Re:I've always wondered... (2)

rrohbeck (944847) | more than 2 years ago | (#38735588)

The question at that point becomes: What do you call life and where is the boundary between non-life or proto-life and "real" life?
Just like you can never observe a speciation event because it is such a slow process and when you look very closely it becomes fuzzy and you have to ask what exactly is a species. Life is always a river and not a thread.

Re:I've always wondered... (2)

tgd (2822) | more than 2 years ago | (#38734148)

Even if it was to happen, the world is a very different place now. A self-replicating bit of RNA or some other precursor is made of things that "real" life wants to eat. Not really any possibility you can evolve from a replicator to something capable of defending itself from advanced life fast enough to avoid the replicator being eaten.

So, it could be happening all the time, but you're just not going to get a whole new form of life out of it, without some privacy and a chance to evolve.

Re:I've always wondered... (0)

Anonymous Coward | more than 2 years ago | (#38734276)

Hold on... in another three nano-centuries the lab will evolve their own yeast-based scientist / philosopher who will then declare carbon-based life forms as primitive. Oops...

Re:I've always wondered... (4, Interesting)

Michael Woodhams (112247) | more than 2 years ago | (#38734344)

In all probability new life (unrelated to current life) cannot evolve on Earth because current life either prevents the required conditions (eating the food before it gets concentrated enough for extremely primitive life to make use of it) or out competing the new life as soon as it arises.

If somehow the Earth were cleansed of all life but otherwise left unaffected, there is no great reason to believe it couldn't re-evolve life. However, as we don't understand the origin of life, there is a possibility that necessary conditions are no longer available - e.g. early life relies critically on the presence of a radioactive nucleotide with half-life of a few hundred million years, present in the early Earth but now decayed.

We find evidence of life in pretty much the oldest rocks on Earth which could contain evidence of life. So in the only instance we can study, life arose about as soon as it possibly could have. This suggests (but does not prove) that given the right conditions, evolution of life is an easy step, rather than one which requires a once-in-a-trillion-years fluke occurance.

However, unicellular life was around for some 2.5 to 3 billion years before multicellular life arose (or at least, multicellular life which left fossil evidence.) This suggests that the step from unicellular to multicellular is hard. Or so I've argued, until this result turned up...

So, we have this result, and the fact that multicellularity has arisen multiple times, and although only in Eukaryotes, it has arisen in very distantly related Eukaryotes (plants vs the fungi/animal clade) suggesting that multicellularity is fairly easy to evolve. So why did it take so long? Perhaps it required a certain level of atmospheric oxygen before multicellular life was viable (plot [wikipedia.org].)

(I have only tangential professional connection to these topics, so these are merely semi-educated ramblings.)

Re:I've always wondered... (1)

rrohbeck (944847) | more than 2 years ago | (#38735644)

Just the presence of oxygen will prevent whatever happened from occurring today. You can't have primeval soup on Earth today. However, I wonder if we shouldn't push the Urey experiment further. I always liked it and it was a big revelation when I read about it for the first time as a kid.

Re:I've always wondered... (2)

Richard.Tao (1150683) | more than 2 years ago | (#38734680)

Huh. That got me thinking quite a bit! Wikipedia shows it's a questions that's been pondered since the father of gradual change himself, Darwin:
He though that self replicating structures could happen, but that... "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed."
And on that subject, "No new notable research or theory on the subject appeared until 1924, when Alexander Oparin reasoned that atmospheric oxygen prevents the synthesis of certain organic compounds that are necessary building blocks for the evolution of life."

It seems like there were some specific circumstances to get life going down a certain path. But now with changed initial conditions and FIERCE competition for resources EVERYWHERE new self reproducing structures don't get too far.

Re:I've always wondered... (1)

arthurpaliden (939626) | more than 2 years ago | (#38734774)

If the laws of physics and chemistry have not changed over the last billion years or so then the process could very well still be happening.

Re:I've always wondered... (0)

Anonymous Coward | more than 2 years ago | (#38734834)

It's been proven many times that the 'genesis' happens in isolation without alternative chemical inputs.

Science has proven that god could exist if he were a scientist.

Yeasty "evolution" (-1)

Anonymous Coward | more than 2 years ago | (#38734002)

Once again, great successes hailed while ignoring the elephant in the room: the researchers cheated by selecting out certain ones (those that sank to the bottom.) in TRUE life-by-incremental-changes, every event is random, including which cells are selected out of the tube to prosper.

Re:Yeasty "evolution" (2)

samkass (174571) | more than 2 years ago | (#38734064)

Actually, the opposite of what you say is true. That's the whole point of using the word "selection" in the phrase "natural selection". Anything that helps the organism survive and reproduce better in its environment is a selective pressure. So if you postulate that there exists somewhere on the planet where multi-cellularism is a selective force, then this experiment replicates those conditions.

Re:Yeasty "evolution" (5, Insightful)

Samantha Wright (1324923) | more than 2 years ago | (#38734108)

Well, it's not that hard to create a similar environment in the real world, they take too long to get grant money for. Consider, for example, a microbe growing in a hot spring that needs a very high temperature to function properly (like every molecular biologist's friend, Thermus aquaticus.) If that thing floats to the top of the pond, it might get cold and die. Evolutionary pressures such as sink-or-die aren't that implausible.

Think of it this way: a random walk will get to every possible location eventually. If you push it in a certain direction, it'll simply get there sooner. But if it doesn't get there when you do, then there's no chance it'll ever get there on its own. Unless they tampered with the genes of the yeast in question, these results are completely legitimate.

Re:Yeasty "evolution" (3, Insightful)

pgward (2086802) | more than 2 years ago | (#38734110)

Once again, great successes hailed while ignoring the elephant in the room: the researchers cheated by selecting out certain ones (those that sank to the bottom.) in TRUE life-by-incremental-changes, every event is random, including which cells are selected out of the tube to prosper.

False.

The purpose of this "selection" was simply to simulate a larger environment. If this occurred in a big place relative to the size of the yeast, let's call this imaginary place the ocean, it is highly likely the yeast wouldn't be contained to a test tube. It would disperse on its own. Selecting certain ones and continuing to examine them is the same as zooming in and following the large ones in the ocean you'd like to examine. The centrifuge is not meant for culling, selective breeding or to "intelligently design evolution in yeast".

N.B. I have no idea about the atmospheric requirements for this experiment as I skipped that part of the original article. For all I know the bigger place could have been a rock, a lake, a cloud or an iceberg. The argument is based upon the false implication that yeast only exists in constrained environments.

Re:Yeasty "evolution" (0)

Daniel Dvorkin (106857) | more than 2 years ago | (#38734238)

in TRUE life-by-incremental-changes, every event is random, including which cells are selected out of the tube to prosper

Crawl back under your rock. In a few hundred million years, your descendants may develop something resembling rudimentary intelligence.

Better Beer? (1)

RedLeg (22564) | more than 2 years ago | (#38734046)

Given the yeast they evolved, "Saccharomyces cerevisiae", does this mean we get better, or more intelligent beer?

Red

Re:Better Beer? (1)

Philomage (1851668) | more than 2 years ago | (#38734120)

Okay, I know that "Saccharomyces cerevisiae" MUST mean something like "sugar eater found in wheat" but why, in that first instant of seeing the post, did my mind flash read "sweet cervix"? If only there were something I could consume that would slow down my intuitive thinking to the point that reading could catch up...

Re:Better Beer? (1)

rrohbeck (944847) | more than 2 years ago | (#38735660)

If my Latin doesn't fail me it means "sugar fungus from beer."
Oh and that fuzzy reading comes with age. You get lazy, don't look closely and in 99.999% of the cases you still read the correct word. Or maybe it's just the brain got *that* good at pattern recognition.

Re:Better Beer? (1)

pgward (2086802) | more than 2 years ago | (#38734124)

Given the yeast they evolved, "Saccharomyces cerevisiae", does this mean we get better, or more intelligent beer?

Red

They couldn't really prove higher intelligence, but 6 packs should now contain 36 beers.

Re:Better Beer? (1)

rrohbeck (944847) | more than 2 years ago | (#38735668)

Yay, intelligent beer design!
That's why I prefer unfiltered wheat beer. The smart yeast collects at the bottom, you shake it up and pour it into your glass. Then you drink it and it goes straight to your brain, improving your intelligence. That's my hypothesis anyway.

Relation to yeast (5, Funny)

pgward (2086802) | more than 2 years ago | (#38734070)

Reading the comments on the physorg page made by intelligent design supporters, I have come to a conclusion. Some of us have not evolved far beyond yeast.

Re:Relation to yeast (2)

Samantha Wright (1324923) | more than 2 years ago | (#38734144)

You'll be pleased to know then that we're exactly as evolved as the yeast: three billion years or so. Some just hide it better.

Re:Relation to yeast (0)

Anonymous Coward | more than 2 years ago | (#38734882)

And they tend to clump similarly, sometimes even to the delicate shape of a flake.

Flocculation (3, Informative)

Wookie Monster (605020) | more than 2 years ago | (#38734086)

Yeast already has a natural ability to flocculate, differing by strain. All they did is use artificial selection to produce a new strain of yeast with higher flocculation. The article mentions that yeast evolved from a multicellular life form and that the next experiment will use single celled organisms which did not evolve this way. I suspect it will take much longer than 60 days to see any results.

Re:Flocculation (2)

qwak23 (1862090) | more than 2 years ago | (#38735570)

According the paper (linked in several other comments, and is much more fascinating than the article), the clumps were not the result of flocculation.

I am looking forward to seeing future experiments with other type of single celled organisms.

Not that impressive (1)

antifoidulus (807088) | more than 2 years ago | (#38734090)

College kids have been doing this for years and years, go walk around any dorm, new species of microscopic life are constantly evolving in the showers.

Actually I thought Eukaryotes were the big jump (4, Informative)

wisebabo (638845) | more than 2 years ago | (#38734132)

Not to diminish the importance of multi-cellularity (and of this discovery) but wasn't the development of Eukaryotes (cells with Nuclei and other differentiated organelles) the big step needed for complex life? I mean with chloroplasts you get plants and mitochondria (or mitoklorines for you Star Wars fans) you get animals.

With multi-cellularity and prokaryotes you get strombolites (algal mats).

That said, it shows that evolution can happen quite quickly and can overcome some serious obstacles in a short amount of time in a very limited scope (a laboratory workbench). When multiplied by geologic ages and oceans of room is it any wonder that life has evolved in so many fascinating ways?

Re:Actually I thought Eukaryotes were the big jump (4, Informative)

Samantha Wright (1324923) | more than 2 years ago | (#38734168)

Yeah... But! There are plenty of fancy single-celled eukaryotes that are fantastically dull. Multicellular life is still a pretty neat thing. You just wait; give molecular biology enough time and we'll see experiments that recreate the emergence of eukaryotes, animals, chordates, mammals, primates, hominids, and finally molecular biologists. Just give 'em time.

Re:Actually I thought Eukaryotes were the big jump (1)

wisebabo (638845) | more than 2 years ago | (#38734368)

Yeah, that's what you think. One tiny little change and we could end up with just a planet in an evolutionary dead-end filled with anoxic bacteria and politicians!

Re:Actually I thought Eukaryotes were the big jump (0)

Anonymous Coward | more than 2 years ago | (#38734562)

Yeah, that's what you think. One tiny little change and we could end up with just a planet in an evolutionary dead-end filled with anoxic bacteria and politicians!

How is that any different than what we have now?

The joy of ignorance (0)

Anonymous Coward | more than 2 years ago | (#38734280)

What we humans don't know is impressive.

the way I see it... (-1, Troll)

larry bagina (561269) | more than 2 years ago | (#38734320)

single-cell life + intelligent designer = multi-cell life.

Re:the way I see it... (2)

icebraining (1313345) | more than 2 years ago | (#38734398)

Except he didn't plan the form, look or workings of the organism, which means he didn't actually design.

Re:the way I see it... (1)

tool462 (677306) | more than 2 years ago | (#38735106)

He designed it to the same extent that some people design software. But that probably says more about the coders than him...

Re:the way I see it... (1)

arthurpaliden (939626) | more than 2 years ago | (#38734784)

If there was an 'intelligent designer' then why are the sewer outflows in the middle of the play ground.

Re:the way I see it... (1)

gmhowell (26755) | more than 2 years ago | (#38735212)

If there was an 'intelligent designer' then why are the sewer outflows in the middle of the play ground.

Because for some people sewer outflows ARE a playground, especially when the playground is under the effects of a red tide.

Re:the way I see it... (0)

Anonymous Coward | more than 2 years ago | (#38735248)

The reason is the same as why skyscrapers have their water and drain conduits located together. They're related, and it simplifies construction.

Having a specialized playground, and a dedicated sewer outflow would only waste energy, proteins and time. Be glad they're not all combined in one super mouth-tongue-ear-butt-navel, because that could've been more biologically efficient. But, we lucked out.

Re:the way I see it... (0)

Anonymous Coward | more than 2 years ago | (#38735376)

Because if there's no grass on the field you should play in the mud.

It's just brewers yeast. (0)

slackware 3.6 (2524328) | more than 2 years ago | (#38734454)

It is cheap source of very good quality proteins, vitamins and minerals I put 2 spoonfulls in my orange juice in the morning. If you do eat it make sure it is the deactivated (dead) kind from the supermarket or health shop or it will start to grow in you.

If they can evolve multicellularity in months... (-1)

Anonymous Coward | more than 2 years ago | (#38734634)

Then surely it should be possible for Chinese people to evolve a conscience. Or a culture.

They fast tracked the first billion or so years (0)

viperidaenz (2515578) | more than 2 years ago | (#38735080)

Now we just have to wait another 1 or 2 billion years and those test tubes will have people inside them
Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...