Octopuses have long captured the fascination of scientists and animal lovers alike for their remarkable intelligence, problem-solving abilities, and adaptive behaviors. Yet, a new breakthrough reveals that their cognitive complexity might be more familiar than we think—drawing an unexpected connection between these invertebrates and humans. The discovery, rooted in evolutionary science, sheds light on the shared origins of intelligence in both species.
Tracing the Connection
Recent research suggests that octopuses and humans may share an evolutionary link dating back 518 million years. This common ancestor, deep in our evolutionary past, could explain why octopuses have evolved such extraordinary intelligence despite their status as invertebrates. The key to this similarity lies in the brain development of both species, which may have followed a remarkably similar trajectory over millions of years.
The study, published in Science Advances, led by Nikolaus Rajewsky from the Max Delbrück Centre for Molecular Medicine in Berlin, highlights the critical role of microRNAs (miRNAs) in this process. MiRNAs are small molecules that regulate gene activity, and they are central to the development of the complex brains found in both humans and octopuses.
According to Rajewsky, the significant expansion of the miRNA gene repertoire in octopuses appears to have been a driving force behind the evolution of their advanced neural systems.
The Role of MicroRNAs in Brain Development
At the heart of this study is the discovery that miRNAs—molecular regulators of gene expression—have played a fundamental role in the brain development of both octopuses and humans. These tiny molecules, responsible for controlling how genes are turned on and off, are essential for the creation of specialized neurons that make complex brain function possible.
Rajewsky’s research reveals that the soft-bodied cephalopods, including octopuses, underwent a massive expansion of their miRNA gene repertoire. This expansion, it seems, allowed the animals to develop a more diverse range of neuron types, which in turn contributed to the advanced cognitive abilities that set them apart from other invertebrates.
As Rajewsky explained, “We show that the major RNA innovation of soft-bodied cephalopods is a massive expansion of the miRNA gene repertoire,” a leap in evolution that mirrors similar innovations found in vertebrates.
Convergent Evolution: Different Paths, Same Outcome
Perhaps the most striking aspect of this discovery is the phenomenon known as convergent evolution—where different species evolve similar traits independently due to similar environmental pressures or genetic mechanisms. In this case, despite the vast evolutionary gulf between humans and octopuses, both species appear to have developed complex brains in a remarkably similar manner.
This insight challenges traditional views of animal intelligence, offering a new perspective on how cognitive abilities might arise in unrelated organisms. It suggests that certain biological strategies, such as the expansion of miRNA genes, may be favored by evolution when building highly intelligent brains, regardless of the organism’s physical or evolutionary makeup.
The idea that octopuses and humans could have reached similar levels of brain complexity through distinct evolutionary paths underscores the broader potential for intelligence to emerge in various forms across the animal kingdom.