On the trail of the epigenetic code

Test system on Drosophila should provide the key to histone function

The genetic inherited material DNA was long viewed as the sole bearer of hereditary information.

The function of its packaging proteins, the histones, was believed to be exclusively structural.

Additional genetic information can be stored, however, and passed on to subsequent generations through chemical changes in the DNA or histones. Scientists from the Max Planck Institute for Biophysical Chemistry in Göttingen have succeeded in creating an experimental system for testing the function of such chemical histone modifications and their influence on the organism.

Chemical modifications to the histones may constitute an "epigenetic histone code" that complements the genetic code and decides whether the information from certain regions of the DNA is used or suppressed. (EMBO reports, November 1, 2010, advance online publication)

The condensation of the DNA involves a dramatic restructuring of the two metre-long DNA thread to a chromosome that has a diameter of 1.5 micrometres. The DNA is wound around the packaging proteins called "histones".