Octopuses are smart creatures with sophisticated intelligence, and now scientists have uncovered a clue that may partly explain the remarkable intelligence of cephalopods: its genes have a genetic quirk that’s also seen in humans, according to a new study.
The clues that scientists have discovered are called “jumping genes”, or transposons, and they constitute 45% of the human genome. Jumper genes are short sequences of DNA with the ability to copy and paste or cut and paste to another location in the genome, and they have been linked to the evolution of genomes in several species. Genetic sequencing has recently revealed that two species of octopus – common octopus and bimaculoid octopus — also have transposon-filled genomes, according to a study published May 18 in the journal BMC Biology.
In humans and octopuses, most transposons are dormant, either shut down due to mutations or prevented from replicating by cellular defenses, the study authors reported. But one type of transposon in humans, known as Long Interspersed Nuclear Elements or LINE, can still be active. Evidence from previous studies suggests that LINE jumping genes are tightly regulated by the brainbut are still important for learning (opens in a new tab) and for memory formation in the hippocampus.
When scientists took a closer look at octopus jumping genes that could freely copy and paste around the genome, they discovered transposons from the LINE family. Graziano Fiorito, study co-author and biologist at the Anton Dohrn Zoological Station (SZAD) in Naples, Italy, told Live Science.
Related: Octopuses torture and eat each other after mating. Science finally knows why.
In the new study, the researchers measured the transcription of an octopus transposon by RNA and translation into protein, and they detected significant activity in areas of the brain related to behavioral plasticity – how organisms change their behavior in response to different stimuli. “We were very happy because this is kind of proof,” said study co-author Giovanna Ponte, a researcher in the Department of Biology and Evolution of Marine Organisms at SZAD.
Even though octopuses are not closely related to backbone animals, they still demonstrate behavioral and neural plasticity similar to that of vertebrates, Fiorito added. “These animals, like mammals, have the ability to continuously adapt and solve problems,” and this evidence suggests the similarity may come from the genetic level, he said.
These findings not only link jumping genes to octopus intelligence, but they also suggest that LINE transposons do more than just jump. Rather, they have some role in cognitive processing, the authors suggested in a statement. Because jumping genes are shared by humans and octopuses, they may be good candidates for future research into intelligence and how it develops and varies between individuals within a species, according to the study.
However, since octopuses are quite distant from humans on the tree of life, it is possible that active LINE transposons in both groups are an example of convergent evolution. This means that their contribution to intelligence evolved separately in the two lineages, rather than coming from a common ancestor, the scientists reported.
Originally posted on Live Science.