What octopus and human brains have in common

The cuttlefish is an intelligent animal with a complex nervous system. A team led by Nikolaus Rajewsky of the Max Delbrck Center has shown that their evolution is linked to a dramatic expansion of their microRNAs.

The last known common ancestor of humans and cephalopods is a primitive wormlike animal with little intelligence and simple eye spots. The kingdom can be divided into two groups of organisms. The development of large and complex brains with diverse cognitive abilities was not done by insturments. The only exception is the cephalopods.

The nervous system only developed in these mollusks, and scientists have been wondering why. An international team led by researchers from the Max Delbrck Center in the United States has come up with a possible explanation. In a paper published in Science Advances, they explain that the microRNAs in the neural tissue of the octopus are similar to the microRNAs in the brain of a fish.

Professor Rajewsky is the head of the Systems Biology of Gene Regulatory Elements Lab at the Max Delbrck Center. He says that it's likely that the development of complex brains is influenced by the role of miRNAs.

Rajewsky read a publication about genetic analyses done on animals. The scientists discovered that the cephalopods use certain enzymes that can recode their genes.

Rajewsky said that he thought that the octopuses could have other tricks up their sleeves. He collaborated with the Stazione Zoologica Anton Dohrn in Naples, which sent him samples of 18 different tissue types from dead octopuses.

There was a lot of editing going on, but not in areas that we believe to be of interest. The expansion of a group of genes called microRNAs was the most interesting discovery.

Most of the novel miRNA families were found in the brain. The team believes that the genes were beneficial to the animals and that they are functionally important.

Rajewsky has been researching for two decades. Instead of being translated into messengerRNAs, which are the instructions for production in the cell, these genesEncode small pieces ofRNA that bind to messengerRNA and influence production The conserved binding sites are another sign that the novel miRNAs are important.

The new families are made of microRNAs.

"This is the third- largest expansion of microRNA families in the animal world, and the largest outside of vertebrates," says lead author Grygoriy Zolotarov, MD, a Ukrainian scientist who spent time in Rajewsky's lab. Oysters, which are also mollusks, have acquired just five new microRNA families since the last ancestors they shared with octopuses.

Zolotarov says that oysters are not known for their intelligence.

Rajewsky's interest in the sea creature began when he visited the Monterey Bay Aquarium. We looked at each other after I saw this creature sitting on the bottom of the tank. He says that looking at an animal is very different to looking at a fish. Humans have similar eyes to that of the occidental.

There is an evolutionary perspective to the unique nature of the octopus. There is a central brain and a peripheral nervous system in them. The tentacle can still move even if it is lost. The reason for the development of complex brain functions in octopuses is because they use their arms very deliberately.

They are very curious and can remember things, and that's one sign of intelligence. They can identify people and like some more than others. Researchers think they dream because they change their color while sleeping.

There are alien-like creatures.

According to Rajewsky, if you want to meet an alien, go diving and befriend an animal. He wants to form a European network that will allow more interaction between the scientists. Although the community is small, Rajewsky claims that interest in octopuses is growing around the world.

He says it's fascinating to look at a form of intelligence that wasn't created by us. They lose interest if you use small snacks as rewards. Rajewsky said that his colleagues told him that.

Zolotarov says that the tools they used to create their models were very limited. We don't know which types of cells express the new microRNAs. Rajewsky's team is planning to apply a technique developed in Rajewsky's lab which will allow them to see the cells at a specific level.

The emergence of the complex octopus brain is linked to MicroRNAs. www.science.org/doi/10.1126/sci Adv.add9938

Journal information: Science Advances