Measuring genetics, 5-mC and 5-hmC at single-base resolution

DNA comprises molecular information stored in genetic and epigenetic bases, both of which are vital to our understanding of biology. In human genomes, an epigenetic modification at the fifth carbon of cytosine bases comprises one fundamental pathway by which genes can be silenced or activated . Methods widely used to detect epigenetic modifications at cytosine bases rely on either deamination of unmodified cytosines to read as thymine or borane reduction of the modified oxidised cytosine bases to read as thymine. As a result, such methods fail to capture common C-to-T mutations, and importantly also fail to distinguish 5-methylcytosine (5mC - mainly found in silenced parts of the genome) from 5-hydroxymethylcytosine (5hmC - enriched in active gene bodies and enhancers). Hence, existing methods are unable to read the complete information stored in our genomes in a single workflow. Here, we build on biomodal's duet multiomics solution +modC, which has the unique ability to read genetic and epigenetic cytosine modifications (modC) in a single workflow. By introducing a high-fidelity methyltransferase during the workflow, we are able to construct an expanded information table that can be used to deconvolute A,T,C,G, 5-mC and 5-hmC simultaneously in a single read within a DNA molecule . We use a mouse embryonic stem cell-line, ES-E14TG2A, to map for the first time a simultaneous reading of the genome and epigenome at high depth and show how these epigenetic modifications are segregated across the genome. In summary, using our modified approach we demonstrate simultaneous, phased reading of all six genetic and epigenetic bases. This tool provides a more complete picture of the information stored in genomes and will have applications throughout biology and medicine. 4 technical replicates, each 80ng input extracted gDNA material run in 6-base sequencing workflow as provided by biomodal