Aussie Scientists Upend Conventional Understanding Of Evolution

The theory of how living organisms made the leap from single-celled to multi-celled has been turned on its head by researchers at Australia's University of Queensland (UoQ), following the publication of their findings on Thursday

SYDNEY, (APP - UrduPoint / Pakistan Point News - 13th Jun, 2019 ) :The theory of how living organisms made the leap from single-celled to multi-celled has been turned on its head by researchers at Australia's University of Queensland (UoQ), following the publication of their findings on Thursday.

Using new technology, husband-and-wife team, Bernie and Sandie Degnan proved that the first multicellular animals probably weren't like the modern-day sponge cells, as was commonly thought, but were more like a collection of convertible cells, similar to stem cells.

"This is somewhat intuitive as, compared to plants and fungi, animals have many more cell types, used in very different ways - from neurons to muscles, and cell-flexibility has been critical to animal evolution from the start," Professor Bernie Degnan said.

The leap from single celled to multi celled organisms represents one of the most crucial transitions in our evolutionary history.

"With multicellularity came incredible complexity, creating the animal, plant, fungi and algae kingdoms we see today," Bernie Degnan said.

For decades, scientists believed that multi-celled animals evolved from a single-celled ancestor resembling a modern sponge cell known as a choanocyte.

However, by mapping individual cells, the Degnans were able to compare similar types of cells over time, teasing out the evolutionary history of individual cell types by comparing their "signature".

"Biologists for decades believed the existing theory was a no-brainer, as sponge choanocytes look so much like single-celled choanoflagellates," Associate Professor Sandie Degnan said.

"But their transcriptome signatures simply don't match, meaning that these aren't the core building blocks of animal life that we originally thought they were," Sandie Degnan said.

The revelation reframes the way we think about evolution, helping to better understand our own biology with potentially far reaching consequences.