A study by the Center for Genomic Regulation of Barcelona Over the placozoansmarine animals approximately one millimeter in size, reveals the origin of neurons of more complex animals.
Placozoans are tiny animals They feed on algae and microbes, and live on rock surfaces and in warm, shallow seas. These creatures, shaped like a flattened disc, are found among the simplest animals knownsince they lack body parts or organs.
Scientists believe they appeared on Earth a few years ago. 800 million years and they are 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).
For the new study, published in the journal cellthe authors used a series of molecular techniques and computational models to understand How different types of cells evolved of placozoans.
“Intermediate” cells
The study shows that the nine main cell types of placozoans appear to be connected by “intermediate” cells that change from one type to another.
To maintain the delicate balance of cell types needed for an animal to move and eat, The cells grow and divide. However, the researchers also found fourteen different types of peptidergic cells, which were distinguished from the others by showing neither intermediate types nor signs of growth or division.
Surprisingly, these peptidergic cells share many similarities with neuronsa type of cell that is believed to have appeared millions of years later in the common ancestor of bilaterians and cnidarians.
Comparative analyzes between species revealed that these similarities are unique to placozoans and do not appear in other older animals, such as sponges or ctenophores.
