A result that contradicts years of scientific tradition: this is the conclusion reached by Professor Bernie Degnan of the University of Queensland who, together with his colleagues and using new technology, studied how multicellular beings developed.
The study, published in Nature, states that the cellular structure of the first multicellular animals on Earth does not resemble those of modern sponges but probably that of a stem cell.
This statement therefore disproves the long-standing idea that multicellular animals on Earth have developed from a monocellular ancestor similar to a modern-day coanocyte, a cell type from the gastric cavity of today’s porifers.
One reason that would encourage support for Degnan’s theory would be that, as the scientist himself reports, multicellularity has led to incredible complexity so much so that today’s multicellular organisms differ from over 99% of all biodiversity that can only be seen under a microscope.
According to Sandie Degnan, senior author of the study, the transcriptomic signatures of today’s sponges and choanoflagellates, the monocellular organism considered the closest relative to the animals, do not coincide and this “means that these are not the basic building blocks of animal life that we originally thought they were.”