Octopuses, squid, and cuttlefish possess some of the most sophisticated nervous systems in the animal kingdom, giving them remarkable abilities such as solving problems and rapidly changing their appearance to blend into their surroundings. But how did these extraordinary capabilities evolve? Scientists have uncovered a surprising clue that may lie not in the genes themselves, but in the way DNA is folded and arranged inside cells.
Researchers at the University of Vienna discovered that a massive reorganization of DNA hundreds of millions of years ago brought previously separated genetic regions into contact. These newly formed connections changed how genes could interact and be controlled, potentially helping drive the evolution of the unusually complex nervous systems found in these animals, which are collectively known as coleoid cephalopods. The findings, published in Nature Communications, suggest that the physical structure of DNA may play a much more active role in evolution than scientists once thought.
How the 3D Structure of DNA Influences Evolution To investigate this possibility, the research team reconstructed the three-dimensional organization of the genome in octopuses, squid, and cuttlefish. They then compared the arrangement of DNA with patterns of gene activity to understand how changes in genome structure might influence biological complexity. "The genome isn't just a sequence of genes.
It's folded into a complex three-dimensional structure," said lead author Dr. "Understanding how that structure evolves is becoming increasingly important for understanding how new forms of biological complexity arise." Although DNA is often pictured as a long, twisted ladder, it does not simply stretch out inside a cell. Instead, it folds into an intricate three-dimensional arrangement, allowing sections that are far apart along the DNA sequence to come into close physical contact.
These connections matter because they can influence which genes are activated, when they are used, and how strongly they function. Changes in the way DNA folds can therefore alter gene activity without necessarily changing the underlying genetic instructions. An Ancient DNA Reshuffling Created New Genetic Connections The researchers found evidence that cephalopod genomes underwent an extensive period of reorganization hundreds of millions of years ago.
During this evolutionary upheaval, large sections of genetic material were rearranged, bringing regions of chromosomes that had previously been separated into close proximity. This reshuffling created opportunities for DNA regions to interact in ways that had not previously been possible. Once these connections formed, they could influence each other's activity, gradually establishing more elaborate networks of genetic regulation.
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