Scientists who watched neurons connect inside the eyes of growing squid discovered a fascinating secret – the brains of cephalopods independently evolved to develop in the same way as our own.
The discovery was made using high-resolution cameras focused on the retinas of longfin squid (Doryteuthis pealeii) embryos, despite 500 million years of divergent evolution, the basic blueprint for how brains and complex nervous systems develop may be the same across a wide range of species.
Intelligence Cephalopods – a class of marine animals that includes octopuses, cuttlefish and cuttlefish – has long been a subject of fascination among biologists. Unlike most invertebrates, these animals have remarkable memories; use tools to solve problems; It excels at camouflage. You react with curiosity, boredom, or even The terrifying hatred into their surroundings and they can dream, if the ripples of color flashing across their skin as they sleep are any indication.
Now, this new study published December 5, 2022 in the journal Current BiologyHe suggests that key parts of the formula for advanced intelligence, on Earth at least, remain the same.
Related: Octopuses may be terrifyingly intelligent because they share the genes for intelligence with humans
“Our conclusions were surprising because much of what we know about the development of the nervous system in vertebrates had long been thought to be specific to this lineage,” study senior author Christine Koenig, a Harvard molecular biologist, said in a statement. “By noting the fact that the process is very similar, what you have suggested to us are these two things [lineages] He independently developed very large nervous systems using the same mechanisms to build them. What that indicates is that those mechanisms — those tools — that animals use during development may be important for building large nervous systems.”
To study the developing brains of cuttlefish embryos, the scientists used fluorescent dyes to label a special type of stem cell called neural progenitor cells, before studying how they developed using regular 10-minute snapshots from microscopic cameras. The cameras looked at the retina, where roughly two-thirds of the squid’s nervous tissue resides.
Just as in vertebrates, the researchers saw squid progenitor cells arrange themselves into a structure called a pseudoidentical epithelium—a long, densely packed structure that is a critical step in the development of large, complex tissues. The researchers noted that the size, organization, and movement of the nucleus structure was remarkably similar to the same vertebrate neuroepithelium. Something that was once considered a unique feature that enabled back-brained animals to develop well-developed brains and eyes.
This isn’t the only time scientists have discovered cephalopods share common neural blueprints with us. Like humans, octopuses and squid also have a large variety of microRNAs (small molecules that control how genes are expressed) residing within their nervous tissues.
Next, the team wants to look at how and when different types of cells emerge in the squid as the tissue grows and compare this process to that observed in vertebrate embryos. If the growth chart is the same, then maybe the schedule will be too.
“One of the great things to learn from this kind of work is how important it is to study the diversity of life,” Koenig said. “By studying this diversity, you can really go back to even the most basic ideas about our development and our biomedical questions. You can really talk about those questions.”
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