Abstract
Epigenetic states are governed by DNA methylation and a host of modifications to histones bound with DNA. These states are essential for proper developmentally regulated gene expression and are perturbed in many diseases. There is great interest in identifying epigenetic mark placement genome wide and understanding how these marks vary among cell types, with changes in environment or according to health and disease status. Current epigenomic analyses employ bisulfite sequencing and chromatin immunoprecipitation, but query only one type of epigenetic mark at a time, DNA methylation, or histone modifications and often require substantial input material. To overcome these limitations, we established a method using nanofluidics and multicolor fluorescence microscopy to detect DNA and histones in individual chromatin fragments at about 10 Mbp/min. We demonstrated its utility for epigenetic analysis by identifying DNA methylation on individual molecules. This technique will provide the unprecedented opportunity for genome wide, simultaneous analysis of multiple epigenetic states on single molecules.