Efficient Copy Number Profiling from Human Tumor Methylome obtained by Bisulfite Sequencing

Chromosome copy number variations and DNA methylation alterations are described as two main mechanisms involved in tumoral progression. However, to date there are no methods that allows studying these two mechanisms in a single experiment. This study show that copy number analysis can be realized using data of whole genome sequencing after bisulfite treatment. The comparison of copy number profiling performed on bisulfite converted (BS-Seq) and unconverted DNA sequencing of the same human tumoral sample reveals identical profiling. Moreover, we compared copy number profiles obtained from whole genome sequencing analysis and from DNA microarray analysis and show that BS-Seq as DNAseq are more sensitive than microarrays. Taken together, these results demonstrate the possibility to analyze copy number variations from BS-Seq data which give the opportunity to investigate the relationship between genetic and epigenetic mechanisms in a single experiment and with higher resolution.