How to determine location of oxidised form in genome. 2 general strategies htat people have developed to determine location of oxidised form. Based on antibodies or click chemistry based to specifically tag bisulphite or hydroxyl carboxyl c and determine enrichment across genome. Provides critical info about potential functions in context of gene regulation. Relative abundance of different forms of modifications are distinct, not evenly distirbuted across different states. Major advantage for ace-seq produces base resolution data but also loses far less input dna while producing high resolution profiles. Raw data in the genome browser view for locus of mouse genome we can see wt escs. Because ability to determine level and location of hmc in genome, can resolve base ambiguity because can subtract bisulphite and ace-seq signal to see true signal. First slide for heterochromatin, it"s important because it talks about how there"s a difference between actively repressed chromatin and something that is silenced.