The octopus is a highly intelligent creature with a soft body that can rapidly alter its shape and slip through impossibly narrow openings. It also has the uncanny ability to change color at will to blend into its surroundings. It turns out that this strange creature evolved differently from nearly every other organism on the planet. Actually, it did not evolve, so much as it programmed its own RNA instead – amazing!
Here’s the story…really good eyesight is a handy thing to have in the murky depths of the ocean. Scientists have discovered that the octopus has a unique way to visualize its surroundings. Research indicates the creature’s skin contains the same pigment proteins found in its eyes, so the skin responds to light and can help the octopus ‘see’ what is nearby. Pretty amazing, right? Well check this out – when the octopus’ skin changes colors, it isn’t just responding to instructions from the brain and eyes – it’s actually reacting directly to the surrounding light and changing color all by itself!
Chromatophores are very small, pigmented organs packed with chemicals. Thousands of these chromatophores are packed just below the top layer of skin of an octopus. As the muscles around them expand and contract, the color they display changes.
To pull off this amazing mimicry, the octopus must first sense the surrounding environment and then display its amazing blending ability. Sensing without blending is useless – and blending without sensing is useless. You need both, and that is beyond the reach of random mutations produced through normal evolution. An unreasonably large number of mutations would be required to produce either outcome separately, let alone together.
When an organism changes in some fundamental way, it typically starts with a genetic mutation – a change to the DNA. In a surprising twist, scientists have discovered that octopuses (along with some squid and cuttlefish species) routinely edit their RNA sequences to adapt to their environment.
This is a startling discovery. There is little or no RNA editing in most other species on the planet. But in the octopus, there is evidence of extensive RNA editing and re-coding. When such an edit happens, it changes how the proteins work, allowing the organism to fine-tune its genetic information without actually undergoing any genetic mutations – pretty amazing!