The complex behavior and intelligence of cephalopods are explained by the three-dimensional shape of their genome, not just by individual genes, infohub.kz reports.
Biologists at the University of Vienna studied octopuses, cuttlefish and squid. Inside the cell nucleus, DNA does not lie as a straight thread but folds into a complex three-dimensional structure. This folding brings distant parts of the genome close together, allowing regulatory elements to directly influence the activity of neighboring genes. The analysis showed that hundreds of millions of years ago, the ancestors of mollusks underwent a large-scale restructuring of the genome that brought previously isolated zones together.
It turned out that different levels of DNA structure changed at different rates. Large blocks remained stable throughout evolution and preserved the organism's basic life functions. At the same time, small chromatin loops connecting distant parts of DNA were flexible and actively rearranged between species and tissues. Many of these loops formed near genes responsible for the development of the nervous system.
The scientists called this process "regulatory entanglement." In their view, the physical packing of DNA threads did not merely reflect genetic mutations but itself became a driver of evolution. It created a flexible network for controlling genes, which ultimately allowed mollusks to develop a unique nervous system and master solving complex tasks.