Humans and octopuses share ancestor that lived 518M years ago
Story by Stacy Liberatore For Dailymail.com •
Octopuses and humans descended from the same primitive worm-like animal that lived 518 million years ago, and this could be why the eight-limbed creatures are highly intelligent.
The creature, known as Facivermis yunnanicus, is the earliest known example of animals evolving to lose body parts it no longer needed and was minimally intelligent.
A new study led by Max Delbruck Centre, Berlin found octopuses' brains are similar to humans because the marine animal has a variety of gene regulators called microRNAs (miRNAs) in their neural tissue comparable to the number in vertebrates.
The findings suggest miRNAs, a type of RNA gene, play a fundamental role in developing complex brains.
And this is 'what connects us to the octopus,' co-author Professor Nikolaus Rajewsky said in a statement to SWS.
Octopuses possess a variety of gene regulators called microRNAs (miRNAs) in their neural tissue compared with the number in vertebrates, which means their brains are similar to humans. This could explain their high intelligence© Provided by Daily Mail
Octopuses are renowned for being clever. They can use tools, carry coconut shells for shelter, stack rocks to protect their dens and use jellyfish tentacles for defense, SWNS reports.
Scientists have long studied the intelligence of octopuses, watching them learn to solve puzzles and open screw-top jars.
Recently they were even filmed throwing rocks and shells at each other.
Octopuses belong to a group known as cephalopods - which also include squid and cuttlefish.
The study analyzed 18 different tissue samples from dead octopuses and identified 42 novel miRNA families - mainly in the brain.
The genes were conserved during cephalopod evolution - being of functional benefit to the animals.
'There was indeed a lot of RNA editing going on, but not in areas that we believe to be of interest,' said Rajewsky.
The creature, known as Facivermis yunnanicus, is the earliest known example of animals evolving to lose body parts it no longer needed and was minimally intelligent© Provided by Daily Mail
The study analyzed 18 different tissue samples from dead octopuses and identified 42 novel miRNA families - mainly in the brain. The genes were conserved during cephalopod evolution - being of functional benefit to the animals© Provided by Daily Mail
What was the worm-like animal?
A study in 2020 claimed that a worm that lived on the seafloor 518 million years ago is the earliest known example of animals evolving to lose body parts it no longer needed.
The evolution of Facivermis — a worm-like creature that lived around 518 million years ago in the so-called Cambrian period of China — has long been a mystery.
It had an elongated body that could reach up to 2.2 inches, five pairs of spiny arms near its head and a pear-shaped tail with spikes.
The unusual creature lived a tube-dwelling lifestyle, anchored on the sea floor — because of which it evolved to lose its lower limbs.
'The most interesting discovery was the dramatic expansion of a well-known group of RNA genes, microRNAs.
A total of 42 novel miRNA families were found – specifically in neural tissue and mostly in the brain.'
Given that these genes were conserved during cephalopod evolution, the team concludes they were beneficial to the animals and functionally essential.
Lead author Dr Grygoriy Zolotarov, from the same lab, said: 'This is the third largest expansion of microRNA families in the animal world, and the largest outside of vertebrates.
'To give you an idea of the scale, oysters, which are also mollusks, have acquired just five new microRNA families since the last ancestors they shared with octopuses - while the octopuses have acquired 90.'
Oysters are not precisely known for their intelligence, added Rajewsky, whose fascination with octopuses began years ago while visiting the Monterey Bay Aquarium in California.
He explained: 'I saw this creature sitting on the bottom of the tank, and we spent several minutes - so I thought - looking at each other.
'It's not very scientific, but their eyes do exude a sense of intelligence.' Octopuses have similarly complex 'camera' eyes to humans.
They are unique among invertebrates, with both a central brain and a peripheral nervous system capable of acting independently.
Scientists have long studied the intelligence of octopuses, watching them learn to solve puzzles and open screw-top jars. Recently they were even filmed throwing rocks and shells at each other (pictured)© Provided by Daily Mail
If an octopus loses a tentacle, the tentacle remains sensitive to touch and can still move.
Octopuses are alone in having developed such complex brain functions because they use their arms very purposefully.
The creatures use them as tools to open shells or as a weapon to spat at predators.
They are also very curious and can remember things. They can recognize people and like some more than others.
It is believed they even dream since they change their color and skin structures while sleeping.
Rajewsky said: 'They say if you want to meet an alien, go diving and make friends with an octopus.'
Rajewsky is now planning to join forces with other experts to form a European network that will allow a greater exchange.
What octopus and human brains have in common
IMAGE: OCTOPUSES HAVE COMPLEX “CAMERA” EYES, AS SEEN HERE IN A JUVENILE ANIMAL view more
CREDIT: NIR FRIEDMAN
Cephalopods like octopuses, squids and cuttlefish are highly intelligent animals with complex nervous systems. In “Science Advances”, a team led by Nikolaus Rajewsky of the Max Delbrück Center has now shown that their evolution is linked to a dramatic expansion of their microRNA repertoire.
If we go far enough back in evolutionary history, we encounter the last known common ancestor of humans and cephalopods: a primitive wormlike animal with minimal intelligence and simple eyespots. Later, the animal kingdom can be divided into two groups of organisms – those with backbones and those without. While vertebrates, particularly primates and other mammals, went on to develop large and complex brains with diverse cognitive abilities, invertebrates did not. With one exception: the cephalopods.
Scientists have long wondered why such a complex nervous system was only able to develop in these mollusks. Now, an international team led by researchers from the Max Delbrück Center and Dartmouth College in the United States has put forth a possible reason. In a paper published in “Science Advances”, they explain that octopuses possess a massively expanded repertoire of microRNAs (miRNAs) in their neural tissue – reflecting similar developments that occurred in vertebrates. “So, this is what connects us to the octopus!” says Professor Nikolaus Rajewsky, Scientific Director of the Berlin Institute for Medical Systems Biology of the Max Delbrück Center (MDC-BIMSB), head of the Systems Biology of Gene Regulatory Elements Lab, and the paper’s last author. He explains that this finding probably means miRNAs play a fundamental role in the development of complex brains.
In 2019, Rajewsky read a publication about genetic analyses conducted on octopuses. Scientists had discovered that a lot of RNA editing occurs in these cephalopods – meaning they make extensive use of certain enzymes that can recode their RNA. “This got me thinking that octopuses may not only be good at editing, but could have other RNA tricks up their sleeve too,” recalls Rajewsky. And so he began a collaboration with the Stazione Zoologica Anton Dohrn marine research station in Naples, which sent him samples of 18 different tissue types from dead octopuses.
The results of this analyses were surprising: “There was indeed a lot of RNA editing going on, but not in areas that we believe to be of interest,” says Rajewsky. The most interesting discovery was in fact the dramatic expansion of a well-known group of RNA genes, microRNAs. A total of 42 novel miRNA families were found – specifically in neural tissue and mostly in the brain. Given that these genes were conserved during cephalopod evolution, the team concludes they were clearly beneficial to the animals and are therefore functionally important.
Rajewsky has been researching miRNAs for more than 20 years. Instead of being translated into messenger RNAs, which deliver the instructions for protein production in the cell, these genes encode small pieces of RNA that bind to messenger RNA and thus influence protein production. These binding sites were also conserved throughout cephalopod evolution – another indication that these novel miRNAs are of functional importance.
Cephalopods playing with microRNAs (yellow): microRNAs may be linked to the emergence of complex brains in cephalopods.
CREDIT
Grygoriy Zolotarov
New microRNA families
“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 interned in Rajewsky’s lab at MDC-BIMSB while finishing medical school in Prague, and later. “To give you an idea of the scale, oysters, which are also mollusks, have acquired just five new microRNA families since the last ancestors they shared with octopuses – while the octopuses have acquired 90!” Oysters, adds Zolotarov, aren’t exactly known for their intelligence.
Rajewsky’s fascination with octopuses began years ago, during an evening visit to the Monterey Bay Aquarium in California. “I saw this creature sitting on the bottom of the tank and we spent several minutes – so I thought – looking at each other.” He says that looking at an octopus is very different to looking at a fish: “It’s not very scientific, but their eyes do exude a sense of intelligence.” Octopuses have similarly complex “camera” eyes to humans.
From an evolutionary perspective, octopuses are unique among invertebrates. They have both a central brain and a peripheral nervous system – one that is capable of acting independently. If an octopus loses a tentacle, the tentacle remains sensitive to touch and can still move. The reason why octopuses are alone in having developed such complex brain functions could lie in the fact that they use their arms very purposefully – as tools to open shells, for instance. Octopuses also show other signs of intelligence: They are very curious and can remember things. They can also recognize people and actually like some more than others. Researchers now believe that they even dream, since they change their color and skin structures while sleeping.
Octopuses have both a central brain and a peripheral nervous system – one that is capable of acting independently.
CREDIT
Nir Friedman
Alien-like creatures
“They say if you want to meet an alien, go diving and make friends with an octopus,” says Rajewsky. He’s now planning to join forces with other octopus researchers to form a European network that will allow greater exchange between the scientists. Although the community is currently small, Rajewsky says that interest in octopuses is growing worldwide, including among behavioral researchers. He says it’s fascinating to analyze a form of intelligence that developed entirely independently of our own. But it’s not easy: “If you do tests with them using small snacks as rewards, they soon lose interest. At least, that’s what my colleagues tell me,” says Rajewsky.
“Since octopuses aren’t typical model organisms, our molecular-biological tools were very limited,” says Zolotarov. “So we don’t yet know exactly which types of cell express the new microRNAs.” Rajewsky’s team are now planning to apply a technique, developed in Rajewsky’s lab, which will make the cells in octopus tissue visible at a molecular level.
Max Delbrück Center
The Max Delbrück Center for Molecular Medicine in the Helmholtz Association (Max Delbrück Center) is one of the world’s leading biomedical research institutions. Max Delbrück, a Berlin native, was a Nobel laureate and one of the founders of molecular biology. At the Center’s locations in Berlin-Buch and Mitte, researchers from some 70 countries analyze the human system – investigating the biological foundations of life from its most elementary building blocks to systems-wide mechanisms. By understanding what regulates or disrupts the dynamic equilibrium in a cell, an organ, or the entire body, we can prevent diseases, diagnose them earlier, and stop their progression with tailored therapies. Patients should benefit as soon as possible from basic research discoveries. The Max Delbrück Center therefore supports spin-off creation and participates in collaborative networks. It works in close partnership with Charité – Universitätsmedizin Berlin in the jointly run Experimental and Clinical Research Center (ECRC), as well as with the Berlin Institute of Health (BIH) at Charité and the German Center for Cardiovascular Research (DZHK). Founded in 1992, the Max Delbrück Center today employs 1,800 people and is funded 90 percent by the German federal government and 10 percent by the State of Berlin. www.mdc-berlin.de
JOURNAL
Science Advances
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Animal tissue samples
ARTICLE TITLE
MicroRNAs are deeply linked to the emergence of the complex octopus brain
ARTICLE PUBLICATION DATE
25-Nov-2022
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