New research could link the evolution of complex life to genetic ‘dark matter’

brain learning concept

The findings support the theory that microRNAs play an essential role in the evolution of intelligent life.

New research suggests that microRNAs play a crucial role in advanced brain development, even in humans.

Octopuses have fascinated scientists and the public with their remarkable intelligence, from using tools to engaging in creative play, solving problems, and even escaping from aquariums. Now their cognitive abilities can provide important information for understanding the evolution of life and complex cognition, including the human brain.

An international team of researchers from dartmouth college and the Max Delbrück Center (MDC) in Germany have published a study in the journal

When combined with the known intelligence of octopuses, the findings provide crucial support for the theory that microRNAs are key to the evolution of intelligent life, said co-corresponding author Kevin Peterson, a Dartmouth professor of biological sciences. The nervous systems of octopuses and squids — which both belong to a type of mollusk known as

MicroRNAs were first reported in 1993 by Victor Ambros, a professor at Dartmouth from 1992-2007 who is now a professor at the University of Massachusetts Medical School. For nearly 15 years, Peterson and his research group have sequenced the genes of various animal species in order to link microRNAs to complex tissue development and brain evolution.

For the latest paper, Peterson’s group worked with the lab of co-corresponding author Nikolaus Rajewsky, professor of systems biology at MDC, which had a wealth of

“Every time we’ve tested this hypothesis, we’ve found it very viable, and we’ve not been able to refute it yet. That’s what made this paper particularly exciting,” he said.

Octopuses possess an uncommon intelligence. In 2016, an octopus named Inky made international headlines after escaping from the National Aquarium of New Zealand by slipping through a gap in his tank and pulling himself several feet across the floor to a nearly 150-foot drainpipe leading to the sea — and his freedom. Octopuses also have been observed collecting and building shelters from discarded coconut shells and using water currents to play catch with various objects.

This kind of intelligence potentially stems from microRNAs’ role in diversifying cell function, said study co-author Bastian Fromm, a research group leader at the University of Tromsø in Norway who collaborates with the Peterson lab on its research and building the online microRNA database, MirGeneDB.

Cells in complex organisms perform specialized tasks, which means surrounding cells need to be calibrated to carry out additional functions, Fromm said.

“MicroRNAs are like light switches or dimmers that can turn on and regulate the expression of thousands of proteins in a cell and specify what the cell can do,” Fromm said. “This is a numbers game. Oysters and slugs have microRNAs, but in cephalopods — and especially the octopus — there is an explosion of them that correlates with their intelligence.”

Reference: “MicroRNAs are deeply linked to the emergence of the complex octopus brain” by Grygoriy Zolotarov, Bastian Fromm, Ivano Legnini, Salah Ayoub, Gianluca Polese, Valeria Maselli, Peter J. Chabot, Jakob Vinther, Ruth Styfhals, Eve Seuntjens, Anna Di Cosmo, Kevin J. Peterson and Nikolaus Rajewsky, 25 November 2022, Science Advances.
DOI: 10.1126/sciadv.add9938

The study was funded by the DFG, German Research Foundation; the National Science Foundation;

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