To understand how genes are regulated, researchers create genome-wide maps that connect regulatory proteins to their target sites on the DNA. This analysis is typically performed using “chromatin immunoprecipitation followed by sequencing” (ChIP-seq). With this method, the cell’s chromosomes are cut into small pieces, and an antibody is used to fish out those DNA fragments that are bound by the regulatory protein of interest. Unfortunately, ChIP-seq is a relatively complex protocol that requires a lot of cells, which makes it difficult to analyze some of the most interesting cell types – for example stem cells and cancer initiating cells. Researchers in Christoph Bock’s group at CeMM have developed a new and very efficient alternative to ChIP-seq that addresses these limitations.