Figure 3: The changes on histone peptides levels with MS/MS identification. The error bars were established based on triplicate technical replicates. Figure 3A shows the result of changes on histone modification when normalize to sum of the peak areas corresponding to all observed modified forms of peptides with same primary sequence. Figure 3B shows the result of changes on histone modification when normalize to average peak areas of house-keeping peptides (LVR& EIR). Figure 3C is the result of changes on histone modification when normalize to the sum of the peak areas of all identified peptides.