One of the great mysteries of the human organism lies in the functioning of our command center: the brain. Here are some 900 million connections through 1,600,000 kilometers of wiring between the 100,000 million neurons, that has an adult organ. Are nerve cells They are the most important units of the nervous system. They are responsible for receiving sensory signals from the outside world, sending orders to different parts of the body and transforming and transmitting the electrical signals that allow it. How did we arrive at such a sophisticated system?
Now an investigation published by the magazine Cell sheds new light on the evolution of neurons, focusing on los placozoos, marine animals about a millimeter in size. A scientific team from Center for Genomic Regulation in Barcelona shows that the specialized secretory cells present in these unique creatures they could have given rise to neurons in more complex animals.
Who are these beings? The placozoans are tiny animals, which feed on algae and microbes that live on the surface of rocks and other substrates found in warm, shallow seas. These flattened disc-shaped creatures are among the simplest animals known, having no body parts or organs. They appear on Earth about 800 million years ago and constitute one of the five main lineages of animals, along with ctenophores, sponges, cnidarians (corals, sea anemones and jellyfish) and bilaterians (all other animals, including humans).
“We were amazed by the similarities,” he says in a note. Sebastián R. Najle, first co-author of the study and postdoctoral researcher at the Center for Genomic Regulation. “The peptidergic cells of Placozoans have many similarities with neuronal cells, although they clearly are not. “It’s like observing an intermediate step in the evolution of neurons.”
Placozoans coordinate their behavior thanks to peptidergic cells that release small peptides that allow the movement or feeding of the animal to be coordinated. Driven by the curiosity about the origin of these cellsthe study authors used a series of molecular techniques and computational models to understand how different types of placozoan cells evolved and reconstruct what our ancestors might have looked like and functioned.