Scientists have made a surprising discovery about squid, according to a new paper in the journal eLife. When genes are read, cells copy the information encoded in DNA to produce messages called RNA. This RNA is then used as the instructions to create proteins - the building blocks of the cell.
For a long time it was thought that RNA was a faithful copy of the DNA template, but itís now known that some of the letters in the RNA messages can be changed - a process known as RNA editing. There are examples of editing in many organisms, including humans, worms and fruit flies, but itís not thought to be a hugely widespread phenomenon.
Now researchers in Puerto Rico have discovered that squid edit their RNA on a massive scale, with around 60 per cent of their RNA being edited in the brain - corresponding to an incredible 57,000 sites that differ from the original DNA, compared to around 100 known sites in humans and 600 in fruit flies. The scientists think this might create more diversity in the proteins that are in the squid brain, helping the animals to quickly adapt to changes in their environment such as alterations in temperature.
Well, that is remarkable. To mind comes the phenomenon of monarch butterflies whose migration takes several insect lifetimes, raising the question: How do subsequent generations who have never seen where they came from, know how to get back home? The first thing that comes to mind is that they simply have been programmed by evolution to do so; but if that is so, then the species ought to be very inadaptable to changes that might occur in its environment, unless, of course, the butterflies really do not know where they are going, but simply go off in an assortment of directions, most dying out but those lucky enough to choose the right path complete the cycle. Such a hypotheses requires no knowledge, except the most rudimentary, to be conveyed from one generation to the next. But is it supported by evidence? If not, we are stuck with deciding how generations learn in some detail from preceding generations, or accepting that the species is incapable of any appreciable rate of adaptation to environmental changes. If the evidence demonstrates that the butterflies do in fact learn in some detail and are also adaptable to changes that take place on a human time scale, then we would be forced to ask how this detailed knowledge is transmitted. That it might be transmitted via purposeful manipulation by a species of its own genes is a viable theory but also an astonishing concept. However, before exploring this question further, we need to know whether there is solid evidence that substantive intergenerational information transfer in fact occurs. Atomic-S, Thu, 16th Apr 2015