Charting the epigenome

Until recently, the chemical marks littering the DNA inside our cells like trees dotting a landscape could only be studied one gene at a time. But new high-throughput DNA sequencing technology has enabled researchers at the Salk Institute for Biological Studies to map the precise position of these individual DNA modifications throughout the genome of the plant Arabidopsis thaliana, and chart its effect on the activity of any of Arabidopsis’ roughly 26,000 genes.