from the how-did-we-get-so-large-and-complicated? dept.
Single Cells Evolve Large Multicellular Forms in Just Two Years:
[William C.] Ratcliff wondered what would happen to snowflake yeast grown that long — would they eventually achieve large size? Would that lead to differentiation?
The snowflake yeast achieved multicellularity readily, but their clumps remained microscopic, no matter what Ratcliff tried. For years he failed to make progress, and he credits Ozan Bozdağ, a research scientist at Georgia Tech who was a postdoc in Ratcliff’s lab, with breaking through the wall.
[...] Oxygen can be very helpful for living things, because cells can use it to break down sugars for massive energy payouts. When oxygen isn’t present, cells must ferment sugars instead, for a smaller usable yield. All along, Ratcliff had been growing yeast with oxygen. Bozdağ suggested growing some cultures without it.
Bozdağ began the selection experiments with three different groups of snowflake yeasts, two that could use oxygen and one that, because of a mutation, could not. Each group consisted of five genetically identical tubes, and Bozdağ mounted them in a shaking machine. Around the clock, the yeast were shaken at 225 revolutions per minute. Once a day, he let them settle on the counter for three minutes, then used the contents of the bottom of the tube to start fresh cultures. Then, back in the shaker they went. Every day in 2020 and early 2021, even during the lab closures of the COVID-19 pandemic, Bozdağ was there, with a special exemption granted by the university, exerting selection on the yeast.
[...] Around day 350, Bozdağ noticed something in one of those tubes. There were clusters he could see with the naked eye. “As an evolutionary biologist … you think it’s a chance event. Somehow they got big, but they are going to lose out against the small ones in the long run — that is my thinking,” he said. “I didn’t really talk about this with Will at the time.”
But then clusters showed up in the second tube. And around day 400, the three other tubes of mutants that couldn’t use oxygen kicked into gear, and soon all five tubes had massive structures in them, topping out at about 20,000 times their initial size. Bozdağ started taking pictures of the clusters with his phone camera. There was no longer a need for a microscope.
Journal References:
1.) William C. Ratcliff, R. Ford Denison, Mark Borrello, et al. Experimental evolution of multicellularity [open], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.1115323109)
2.) Ratcliff, William C., Fankhauser, Johnathon D., Rogers, David W., et al. Origins of multicellular evolvability in snowflake yeast [open], Nature Communications (DOI: 10.1038/ncomms7102)
3.) Dryad Data -- Multicellular group formation in response to predators in the alga Chlorella vulgaris, (DOI: 10.5061/dryad.c5902)
4.) Stefania E. Kapsetaki, Stuart A. West. The costs and benefits of multicellular group formation in algae*, Evolution (DOI: 10.1111/evo.13712)
5.) Light-regulated collective contractility in a multicellular choanoflagellate, Science (DOI: 10.1126/science.aay2346)
6.) J. T. Bonner. PERSPECTIVE: THE SIZE‐COMPLEXITY RULE, Evolution (DOI: 10.1111/j.0014-3820.2004.tb00476.x)
7.) Hammerschmidt, Katrin, Rose, Caroline J., Kerr, Benjamin, et al. Life cycles, fitness decoupling and the evolution of multicellularity, Nature (DOI: 10.1038/nature13884)
(Score: 0) by Anonymous Coward on Thursday September 23 2021, @04:20PM (7 children)
It's the secret dietary supplement that turns Americans into large multicellular lard-asses in just a few years.
(Score: 2) by DannyB on Thursday September 23 2021, @05:05PM (2 children)
Big Macs are the food of the gods. As proof I would point out that a past US President's standard order was:
2 Big Macs, 2 Filet O' Fish (Yuk!), and a large shake.
For some odd reason all scientific instruments searching for intelligent life are pointed away from Earth.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @05:30AM
Did he eat this ALL in one sitting/feeding? I'd yak...
I once ate two BK Whoppers back to back and felt sick to my stomach for the entire rest of the day. Couldn't finish the fries or the rest of the drink I was so full.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @10:42AM
Yeah, but which one of those cured his Covid-19?
(Score: 0) by Anonymous Coward on Thursday September 23 2021, @05:47PM (3 children)
And yet, they still find the time to do lots of science, while everywhere else other than China does... approximately nothing.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @02:51AM
Yep, the world made zero progress until America and Jesus came along.
(Score: 0) by Anonymous Coward on Saturday September 25 2021, @07:07AM (1 child)
As American as Chinese made iPhones.
(Score: 0) by Anonymous Coward on Saturday September 25 2021, @02:21PM
Yes, exactly. It's not where you're from, it's where your at.
(Score: 2) by DannyB on Thursday September 23 2021, @05:15PM (2 children)
An experimenter could tinker with the direction evolution would take in multi cellular organisms.
Create certain environmental pressures which encourage specific adaptations to be selected to evolve.
Get rid of organisms that are too small. Or those that don't consume or alter some substance you want them to clean up. (eg oil)
For some odd reason all scientific instruments searching for intelligent life are pointed away from Earth.
(Score: 0) by Anonymous Coward on Thursday September 23 2021, @07:54PM (1 child)
Dream on, pedo, they're never going to breed children who actually want to go to your basement.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @12:22AM
Sounds like someone is speaking from experience.
(Score: 4, Interesting) by bradley13 on Thursday September 23 2021, @06:17PM (6 children)
Yeast has been multicellular in the past, and apparently the genes are still there. It's not hard to get yeast to be multicellular again. Given that, selecting for larger clumps seems...unsurprising. What may be surprising is that it took a year to get there.
Reminds me somehow of the guy who has been culturing e-coli in forced evolution for something like 30 years. (Here's an article from 2013, his 25th anniversary. [evolutionnews.org]) Every day, take a sample, put them into a fresh medium. And apparently he has kept frozen samples all the way back. Recently, the e-coli apparently started eating some supposedly component of the medium that wasn't supposed to be food.
Everyone is somebody else's weirdo.
(Score: 3, Interesting) by Common Joe on Thursday September 23 2021, @07:10PM (3 children)
I was thinking even if a single celled organism had never been a multi-cellular organism in the past, it would still have genes from multi-celled organisms because genes jump from organism to organism. It's an interesting and worthwhile experiment, but it's definitely not accurate to say that it was completely spontaneous.
(Score: 2) by bradley13 on Friday September 24 2021, @08:02AM (2 children)
That's an interesting point. Apparently mammalian DNA includes a lot of virus segments. Oops? Or were they kept because they are useful? DNA gets swapped all over the place.
Seems to me that the really big jump is cell differentiation that survives reproduction. Getting a bunch of cells to stick to teach other (basic multicellular) is one thing. Having two different kinds of cells accidentally stick together is happenstance. But creating that situation in subsequent offspring - that seems like a huge leap.
Everyone is somebody else's weirdo.
(Score: 2) by Common Joe on Friday September 24 2021, @05:13PM (1 child)
I wasn't even thinking viruses. In the Japanese population, there is a percentage that can digest a particular seaweed using a particular enzyme. The only place they could have gotten it was from a microbe they ate. Although it's very rare, this means, genes jumped from a microbe into another organism by being eaten. Here's the article. [wired.com]
(Score: 0) by Anonymous Coward on Friday September 24 2021, @10:02PM
No, it doesn't necessarily mean they obtained enzyme-producing genes from bacteria. It could just mean that they have the bacteria living in their gut. Everything in the world is covered in bacteria, and those bacteria generally have enzymes which allow them to feed on the stuff they live on or near. Some of them can survive and thrive in the human environment.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @02:31PM (1 child)
It depends on how many mutations are needed to get a beneficial result. If it's just one mutation a lower mutation rate can get there more quickly. If it's multiple mutations it would take much longer. As the number of necessary mutations increases the necessary time required also grows exponentially.
(Score: 0) by Anonymous Coward on Friday September 24 2021, @02:41PM
Also, IIRC, my above comment has been shown experimentally with like fruit flies and bacteria as well (I can't remember exactly). You can somewhat predict how long it would take a given set of mutations to occur and arrive at a desirable and beneficial outcome depending on how many mutations it would take to get there. The more mutations the less likely the outcome/the longer it would take.
(Score: 2) by Rosco P. Coltrane on Thursday September 23 2021, @06:35PM (1 child)
They clump together, then start complaining that ordinary yeast offend their feelings and don't respect their right to identify as multicellular organisms.
(Score: 1, Funny) by Anonymous Coward on Friday September 24 2021, @02:55AM
Then they stop making beer and make artisinal IPAs that cost twice as much. Bah!
(Score: 3, Funny) by Rosco P. Coltrane on Thursday September 23 2021, @06:39PM
Someone badly messed up the latest batch of homebrew and decided to style it out as a groundbreaking genetic experiment.
(Score: 2) by turgid on Thursday September 23 2021, @09:36PM (3 children)
This is proof that God exists and He is not only watching, but participating. I fully expect Bible Volume V to be out soon. Mark my words.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 1, Funny) by Anonymous Coward on Friday September 24 2021, @02:57AM (1 child)
Is that the same prankster God that's burying dinosaur fossils to fuck with us?
(Score: 3, Funny) by FatPhil on Friday September 24 2021, @11:43AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 3, Funny) by krishnoid on Saturday September 25 2021, @09:39PM
I want in on this action! Is it too late to get in on the ground floor [youtu.be] as the new messiah?