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+--- Thread: Research Scientists discover 'unusual' third path to multicellular lifeforms (/thread-15688.html)
Scientists discover 'unusual' third path to multicellular lifeforms - C C - Apr 5, 2024
https://www.sciencealert.com/scientists-discover-unusual-third-path-to-multicellular-lifeforms
EXCERPTS: Just when scientists thought they had almost figured out the origins of multicellular life, evolution throws another curveball.
In a serendipitous discovery, a team of researchers has just chanced upon a third type of 'unconventional' multicellularity that blends the two kinds we already knew about.
Multicellularity has evolved a staggering 45 times or more across the tree of life. Yet fundamentally, the ancestor of each multicellular lineage relied on just one of two methods - individual cells sticking together as they split, or individual cells that have previously split coming back together.
Clonal multicellularity, where cells remain connected as they divide over and over again, gives rise to organisms as simple as filamentous cyanobacteria, and as complex as animals with their specialized tissues.
The other kind of multicellularity, called aggregation, is a temporary clustering of free-living cells, which happens with eerily cooperative slime molds and social amoeba, often in response to harsh environmental conditions or predation.
Núria Ros-Rocher, an evolutionary biologist at the Pasteur Institute in France, and colleagues made their surprise discovery when studying choanoflagellates: single-celled, water-dwelling organisms that form short-lived colonies and represent the closest living unicellular relatives of animals.
[...] Specifically, the team was observing the behavior of a choanoflagellate called Choanoeca flexa.
[...] "We find C. flexa sheets can form through purely clonal processes, purely aggregative processes, or a combination of both, depending on experimental conditions," the team writes in a preprint posted to the bioRxiv preprint server ahead of peer review... (MORE - missing details)