A strange case of intergenerational memory

CHARLES DARWINDNADNADNAAAASDNARNA did not invent the idea of evolution. But he did come up with the currently accepted explanation, natural selection, in which heritable characteristics arise by chance and are retained if competition shows them to be useful. Natural selection’s success overthrew an earlier idea proposed by Jean-Baptiste Lamarck, a French natural historian. Lamarck had suggested that characteristics acquired by experience during an organism’s lifetime might somehow become heritable.Modern genetics has no place for Lamarckism as a long-term mechanism, because it would involve writing the recipe for such environmentally induced changes accurately into an organism’s . But occasional examples of short-term effects that resemble it do turn up from time to time. They usually involve minor and reversible chemical tweaks to the in sperm and eggs, or to the proteins in which that is packaged into chromosomes. These tweaks, known as epigenetic effects, tend to cause general, and not always helpful, responses to events like famine, and persist for only a generation or two. The meeting heard, however, of an example that has a much more intriguing mechanism. It encodes a specific, life-saving behaviour in a relative of called . And it is passed down even unto the third and fourth generations.