Epigenetic changes don't last
Special enzymes transfer methyl groups to the cytosine building blocks of DNA. A methyl group consists of one carbon atom combined with three associated atoms of hydrogen (CH3). Jean-Baptiste Lamarck would have been delighted: geneticists no longer dismiss out of hand his belief that acquired traits can be passed on to offspring. When Darwin published his book on evolution, Lamarck's theory of transformation went onto the ash heap of history. But in the last decade, we have learned that the environment can after all leave traces in the genomes of animals and plants, in form of so-called epigenetic modifications. Scientists at the Max Planck Institute of Developmental Biology in Germany have now produced the first comprehensive inventory of spontaneous epigenetic changes. Using Arabidopsis, the workhorse of modern plant genetics, the researchers determined how often and where in the genome epigenetic modifications occur – and how often they disappear again. They...