The Feulgen reaction: A brief review and new perspectives

The Feulgen reaction has been proposed by Robert Feulgen and Heinrich Rossenbeck for the identification of DNA nearly a hundred years ago. Since then, many other applications of this cytochemical/topochemical procedure at qualitative and quantitative level have been proposed in relation to DNA and its role in chromatin in human, animal and plant cells. In this article, we briefly review some fundamental aspects of the Feulgen reaction and current applications of such a method in studies of altered chromatin texture, including its association with or preceding changes in transcriptional activities and effect on epigenetic marks. Further perspectives on the use of the Feulgen reaction will depend of the proposal of innovative biological questions in which its reveals appropriate.