ISSN 1359-7345 Chemical Communications www.rsc.org/chemcomm Volume 49 | Number 77 | 7 October 2013 | Pages 8563–8720 1359-7345(2013)49:77;1-P COMMUNICATION Yuval Ebenstein et al. Optical detection of epigenetic marks: sensitive quantiication and direct imaging of individual hydroxymethylcytosine bases