The origin of such a complex organ as the brain of vertebrates is still a mystery to scientists. From the point of view of evolution, he came out of nowhere. You will not see anything like that it would be similar to the anatomy of the brain for other types of animals, as noted by Lady Ariel (Ariel Pani), a researcher of the Marine Biological Laboratory (MBL) in Woods Hole and a graduate of the University of Chicago.
But recently in the journal Nature, Pani and colleagues published information on the opening of some genetic processes that govern the development of the vertebrate brain, guinea worm belonging to the class kishechnodyshashih, which the researchers collected in the bay in Uokvoyt in Falmouth (MA).
The scientists were looking for a hereditary confirmation of three "signaling centers" in the vertebrate embryo, which are the main components of the "invisible dispositions that predispose to the development of the brain," as reported by Pani. Diagnostic molecular characteristics of these signaling centers are largely absent in sea squirts and lancelets, invertebrate animals such as chordates, the closest relatives of vertebrates from an evolutionary point of view. This indicates that the signaling data centers are in the new key features of vertebrate origin.
To his surprise, the scientists found a very similar signaling centers in the marine worm species Saccoglossus kowalevskii, gemihordovyh invertebrates.
In the embryos of these worms were absent structure of the nervous system, which are comparable to the vertebrate brain, and their ilk deviated in the development of vertebrates more than 500 million years ago. Pani and his colleagues found that the signaling centers of marine worm affect the formation of his body in the bud.
"This means that the marine worm is the last common ancestor of vertebrates and gemihordovyh. Even if he never had the nervous system as a vertebrate, the presence of some very sophisticated mechanisms characteristic of the nervous system of vertebrates that control development of the body is obvious" - said Pani. "In addition, strange sea creatures such as sea squirts can provide very valuable information for better understanding of the evolution of the vertebrate and genetics."
"Lancelets and sea squirts - it’s the first animals to be studied to understand the evolution of vertebrates. But if there are any differences, we now know that animals should be treated with the divergence in anatomy, because you can find some interesting similarities there, where you do not expect, "- said the Lady. "I think that this principle should be widely used by researchers to better understand the evolution of the animal."
Marine Biological Laboratory, which houses more than 200 different types of marine animals has long been a center for comparative studies of the evolution and development of the animals.