Octopuses stand out as remarkable creatures with brains that are unusually intricate for invertebrates. In some respects, they resemble vertebrates more closely than their invertebrate peers. New findings suggest that the neural and cognitive sophistication of these animals may trace back to molecular similarities with the human brain. The research, conducted by a collaboration including SISSA in Trieste and Stazione Zoologica Anton Dohrn in Naples, points toward shared genetic mechanisms that help explain high-level thinking in both octopuses and humans. [Source: BMC Biology study].
Experiments show that the same set of genes, sometimes referred to as jump-start or jump-up genes, are active in the brains of humans and in two cephalopod species, the common octopus and the California octopus. This parallel hints at a possible common path to intelligence across distant species and opens avenues to understanding what drives complex behavior in animals with very different bodies and lifeways. [Source: BMC Biology study].
Genomic sequencing revealed as early as 2001 that more than 45 percent of the human genome consists of sequences known as transposons, or jumping genes. These mobile elements can move within the genome, effectively copying and pasting themselves to new locations. Their function appears related to cognitive traits such as memory and learning, a link that researchers are now exploring in both humans and octopuses. [Source: BMC Biology study].
In most cases, these mobile elements lie quiet, without obvious effects on living organisms. Some are inactive due to accumulated mutations; others remain intact but are suppressed by cellular defenses. From an evolutionary standpoint, even these dormant fragments serve as raw material that evolution can repurpose, contributing to the development of new traits over time. [Source: BMC Biology study].
Among the mobile elements, long interspersed nuclear elements, or LINEs, stand out. LINEs exist in hundreds of copies within the human genome and can still be active. For many years, LINE activity was viewed as a relic of evolution, but newer evidence suggests that their activity is carefully regulated in the brain and may play a role in neural function. [Source: BMC Biology study].
Some scientists propose that LINE transposons are linked to cognitive abilities like learning and memory. They appear particularly active in the hippocampus, a key brain region involved in learning processes. [Source: BMC Biology study].
A Genome Rich in ‘Jumping Genes’
The octopus genome, much like the human genome, is abundant in jumping genes, though many remain inactive. Focusing on transposons capable of copy-and-paste, researchers have identified LINE elements in areas of the brain tied to cognitive abilities in octopuses. This discovery results from a collaboration among leading research institutes and was enabled by advanced sequencing techniques used for molecular analysis. The study sheds light on how gene activity in the nervous system supports learning and problem-solving in these intelligent creatures. [Source: BMC Biology study].
“Finding an active LINE element in the brains of two octopus species is significant because it supports the idea that these elements have a function beyond simple copy and paste,” notes a leader of the SISSA Computational Genomics laboratory. The published work involved a large international team and contributes to our growing understanding of genome evolution in relation to brain function. [Source: BMC Biology study].
When the strong signal of LINE activity was observed in a key brain region associated with learning, researchers described the octopus brain as a site where cognitive abilities arise, much like the human hippocampus. This finding reinforces the concept that certain molecular processes can converge across very different species to support similar functions. [Source: BMC Biology study].
Experts explain that the similarity between the human and octopus brain can be understood as a case of convergent evolution, where the same genetic mechanism evolves independently to meet similar needs. LINE elements in the brain offer a fascinating glimpse into how regulatory sequences might shape intelligence across diverse life forms. [Source: BMC Biology study].
As one researcher summarized, the octopus brain shares functional parallels with mammalian brains in several respects, and the identified LINE element provides a promising target for future work on the evolution of intelligence. This line of inquiry helps explain how neural networks can arise in very different organisms under common selective pressures. [Source: BMC Biology study].
Reference work: https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-022-01303-5
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[Citations: BMC Biology study; SISSA; Stazione Zoologica Anton Dohrn; Istituto Italiano di Tecnologia]