Last week, I was preparing some solutions in the laboratory. Even though nothing I was working with was more dangerous than what any of you would use for doing laundry, I had dawned a lab coat and was concentrating on weighing out precise amounts to mix into super-filtered water. Even though there was no other person in the room, I had the feeling that someone was watching me. When I turned around, there she was: The octopus in the aquarium behind me had left her hiding place to assess what was happening outside her watery enclosure. Now that I think about it: What did I look like in my white lab coat, seen blurry through her water-adapted camera lens eye?
Later, I saw her moving around her tank, her tentacles reaching out in all directions, feeling and tasting the environment she was in. Intrigued by this creature and her activity, I slid the cover plate aside a little and gently touched a tentacle. Immediately, the octopus grabbed on to my hand, brought a second tentacle out and began to investigate both my arm and the surface of the aquarium.
I did not freak out, because I was not surprised. I indulged her advances for a moment, then gently loosened the suckers from my hand and pushed the tentacle back into the aquarium. For half a minute, we played a game of her reaching out her tentacles and me pushing them back in. Then she changed her tactic and squirted a big gush of water at me. I laughed and used the distraction to get the last tentacle back into the water. Before I could completely close the lid, she squirted another big gush of water, getting my sleeves and making a big puddle on the floor.
Great, now I had to mop up before I could return to my work, but I was still chuckling and shaking my head at this little octopus encounter.
I am not alone in being intrigued by octopi. Here is an animal that has a body plan far different from its closest relatives and an intelligence that seems to have sprung from nowhere.
What I mean by that is that on our evolutionary tree the octopus is at the top of the mollusk branch, on which you also find slugs, snails, limpets, chitons, clams and other bivalves. However, octopi have been shown to learn by observation, use tools and show behavior that seemed to involve planning. For example, there is a story of an octopus that could open its tank cover, slither across the floor into a nearby crab tank, gorge itself and go back home (this did not happen here).
The body plan of the octopus is equally fascinating: It has three hearts, a mini brain in every tentacle connected to a central brain and chemical taste sensors in its thousands of suction cups on its eight tentacles, which can operate independent of each other, and even move when the animal is asleep.
A while ago, my son told me to look up and write about the octopus genome. He had come across an article that said that octopus could alter their genome while they are alive. In his words, the animals were evolving within their own life span. Given that the life span of the Pacific giant octopus is only about four years, this is even more intriguing to think about. Today, I followed his lead and did some reading on the topic. It turns out octopi and their relatives are giving the world of geneticists a lot to think about.
In August 2015, a group of scientists who were deciphering the DNA of octopi released their findings, which included some unexpected and very unusual news. One of the authors made a joke and said that the octopus DNA looked to them unlike anything they had seen before and it might as well be alien. The media loved that statement and plastered the headlines with “squid from space” fantasies. What the scientists actually found was that in octopi and their relatives, squid and cuttlefish, the transcription of the genetic code was more flexible due to a slightly different way of doing it. I am no geneticist, but I will try to explain what I understood:
Think of the DNA as a model instruction. Usually, to make a copy of it, RNA is written, which you can think of as a mold or a print. Every once in a while, the mold is not perfect and a single piece of information is off. This can lead to the copy not being exactly the same as the original and is called RNA editing.
The octopus genome had a lot more RNA editing. It seemed to have maintained the locations of such genome flexibility over millions of years as if protecting them. To get back to our simile, we now have a mold of the DNA, but we build in ways to alter the mold, so it can make different products. I have a chocolate mold for a mermaid: If I replaced the tail with feet, I could make a girl and if I replaced the head with a fish head, I could use the same mold to make a fish. It seems that the octopus genome is flexible in a similar way. Even if it is at this point only speculation, some scientists think that it may be easier to adapt to temporary changes, perhaps even assist learning. The flexibility in the editable genes comes at the cost of less flexibility in the genes around them, which may mean that adaptability to short-term changes may come at the price of slower evolution in other genes. What that means in the long-term: That would be a question for those geneticists in their white lab coats investigating octopus DNA in their sophisticated laboratories.
I don’t claim to have told you about all the secrets found recently in the genetic code of octopi. After the first breakthrough paper in 2015, there were others to follow. Some scientists expanded on details, others disputed some of the findings or interpretations. The men and women in white lab coats in gene labs around the world are talking about octopi. Once again, we may find more amazing things in the depths of the ocean on our planet than in the expanse of space.