In the 1960s, biologist James McConnell conditioned worms to respond to light flashes, then ground them up and fed them to other worms. He reported that those cannibalistic worms learned to respond to flashes faster than non-cannibalistic control worms, suggesting that memory transfer had taken place. Others couldn’t fully replicate McConnell’s results, but clearly something was going on.
More recently, Oded Rechavi, working on other types of worms, showed that small RNAs can be inherited in the germline for multiple generations and affect the expression of genes involved in behavior. This could be seen as a partial vindication of McConnel’s memory transfer experiments, or at least hint at a mechanism how such memory transfer may take place.
The inheritance of acquired traits like memories at the molecular level is called epigenetics. The term is often used as a contrast to genetic inheritance, the inheritance of variation in DNA. The big difference is that epigenetics refers to characteristics that are acquired during an organism’s lifetime and are somehow passed on to the next generation. Genetic inheritance on the other hand assumes that an organism’s experiences during its lifetime doesn’t get passed on, and the only thing that gets inherited is its DNA. Neither concept takes into account the impact of the environment, which obviously also shapes how an organism looks and behaves.
Epigenetics sounds compelling, but there is no evidence for it playing a large role in shaping how organisms look or behave. Compare this to the massive and well-established contributions of genetic inheritance. The experiments of McConnell, Rechavi and others point to something going on, but whatever it is, it’s subtle. RNA and other informational molecules get inherited but mostly constitute noise and don’t play a major role in shaping the organism. In that sense, the situation is similar to junk DNA, which gets transcribed, but that transcription is mostly noise.
Regardless of what has been claimed, epigenetics hasn’t changed our understanding of evolution. Those who believe that epigenetics plays a major role often also believe that group selection has shaped populations and that junk DNA is an outdated concept. They are wrong on all three counts. For reasons that they cannot articulate, they’re unhappy with Darwinism and are looking for alternatives.
Nehaveigur 