Biologists have discovered a surprising similarity between the genetics and minds of humans and octopuses.

Scientists at the Max Delbrück Center for Molecular Medicine have suggested that the complex brain of the human species is similar to that of octopuses. The research was published in the journal Science Advances.

Previous studies have shown that octopuses change their RNA sequences extremely quickly when environmental conditions change. Often, adaptation begins with a change in DNA genes that can be compared to a cookbook and RNA with a recipe written on a separate sheet of paper. Changing information on a piece of paper is much easier than reprinting a book.

The authors of the new study suggested that this flexibility of RNA is somehow related to the repertoire of microRNAs, which are small molecules that can bind specifically to a particular part of RNA. In this case, there is an increase or decrease in the production activity of the substance, for the synthesis of which RNA is responsible.

After analyzing 18 samples from dead octopuses octopus vulgaris, Octopus bimaculoids and squid Euprymna ladlesThe scientists confirmed their hypothesis. In cephalopods, 138 families of miRNAs were found, 42 of which are novel and are mainly found in brain and nervous tissue.

This discovery placed octopuses third in the animal kingdom and first among invertebrates for microRNA diversity. The number of microRNAs in octopuses is the same as in vertebrates such as chickens and frogs.

By comparison, oysters and octopuses once shared a common ancestor. Since then, the first has acquired only five new families of microRNAs, and octopuses – 90. Only once such large-scale uptake has occurred in vertebrates – the human genome encodes about 2600 mature miRNAs.

The researchers say the discovery suggests that complex intelligence, including that of cephalopods, may be related to this microRNA expansion.

A squid’s brain has been proven to be almost as complex as a dog’s. There is even evidence that octopuses can dream, which is rarely confirmed in invertebrates. Unlike other intelligent animals, their nervous systems are highly distributed: a significant portion of the 500 million neurons are scattered around the arms. Each arm is capable of making decisions independently and can continue to respond to stimuli even after separation.