Ancient Ancestor Links Human and Octopus Intelligence Back 518 Million Years

Recent studies indicate that the extraordinary intelligence of cephalopods, such as octopuses, may be traced to a distant evolutionary relative shared with humans. Research highlighted by New Scientist proposes that both lineages inherited cognitive advancements from a common ancestor living approximately 518 million years ago.

Unveiling the Role of MicroRNAs

The foundation of this neural complexity involves microRNAs (miRNAs), tiny molecules that regulate gene expression.

A research team led by Nikolaus Rajewsky at the Max Delbrück Centre for Molecular Medicine discovered that soft-bodied cephalopods, including octopuses, underwent a dramatic increase in their miRNA gene inventory.

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This surge in miRNAs appears crucial in shaping their sophisticated brains, enabling the formation of a variety of neuron types.

The authors emphasized, “We show that the major RNA innovation of soft-bodied cephalopods is a massive expansion of the miRNA gene repertoire,” highlighting the evolutionary significance of this development.

Parallel Paths to Brain Complexity

Remarkably, despite evolving separately, octopus and human brains have developed comparable complexity.

This phenomenon, known as convergent evolution, indicates that similar molecular strategies—particularly involving microRNAs—may be favored by natural selection to build elaborate neural systems across distinctive species.

This insight reveals a common biological blueprint for intelligence that spans diverse forms of life.

3C185A66-C96E-4CCD-8414-77B81E082581-6ef78b62d957be634b172ab2fbd71c73.png — (A) Schematic representation of tissues sampled in the study. Neuronal and non-neuronal tissues are 212 colored in blue and yellow, respectively. Inset (B): brain and surrounding structures. (C) Main 213 sequencing methods and computational analyses used in this study.

Rethinking Animal Intelligence

This research challenges conventional views about cognition in the animal world. Octopuses have always intrigued scientists with their reasoning abilities, adaptability, and inquisitive behaviors, now linked more clearly to their unique RNA expansions.

By revealing the critical influence of microRNAs on octopus neural development, this study opens new possibilities for understanding how intelligence might independently evolve across varied life forms.

The striking cognitive parallels between humans and octopuses suggest that intelligence is a multifaceted trait that may emerge through numerous biological routes.