| Title | Single Cells Evolve Large Multicellular Forms in Just Two Years | |
| Date | Thursday September 23 2021, @04:13PM | |
| Author | martyb | |
| Topic | ||
| 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.
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printed from SoylentNews, Single Cells Evolve Large Multicellular Forms in Just Two Years on 2024-04-25 22:05:37