Introducing the brain: developing squid brain like ours (Introduction)

by David Turell , Wednesday, January 18, 2023, 16:07 (673 days ago) @ David Turell

We split 500 million years ago, but similar embyologic development is found:

https://www.livescience.com/baby-squid-retinas-have-vertebrate-brain-development?utm_te...

"Scientists who watched nerve cells connect inside the eyes of growing squid have uncovered a remarkable secret — the cephalopods’ brains independently evolved to develop in the same way ours do.

"The discovery, made using high-resolution cameras focused on the retinas of longfin squid (Doryteuthis pealeii) embryos, reveals that, in spite of 500 million years of divergent evolution, the basic blueprint for how complex brains and nervous systems evolve may be the same across a wide range of species.

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"'Our conclusions were surprising because a lot of what we know about nervous system development in vertebrates has long been thought to be special to that lineage," study senior author Kristen Koenig, a molecular biologist at Harvard University, said in a statement. "By observing the fact that the process is very similar, what it suggested to us is that these two [lineages] independently evolved very large nervous systems using the same mechanisms to build them. What that suggests is that those mechanisms — those tools — the animals use during development may be important for building big nervous systems."

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"Just as in vertebrates, the researchers saw the squids’ progenitor cells arrange themselves into a structure called a pseudostratified epithelium — a long, densely packed structure that forms as a crucial step in the growth of large, complex tissue. The researchers noted that the size, organization and movement of the structure's nucleus was remarkably similar to the same neural epitheliums in vertebrates; something that was once considered a unique feature that enabled back-boned animals to grow sophisticated brains and eyes.

"This is not the only time that scientists have spotted cephaolopods sharing common neurological blueprints with us. Much like humans, octopuses and squid also have a large variety of microRNAs (small molecules that control how genes are expressed) found inside their neural tissue."

Comment: another example of convergent evolution. From a design point of view, if a mechanism works use it whenever required.