text: In the initial report on this method, a library of ~500 cCRMs was drawn from a variety of genomic data sources (e.g., TF-bound regions, coactivator-bound regions, DNase I hypersensitive sites, and predictions from the Bulyk lab’s PhylCRM algorithm ) by PCR from genomic DNA, and then screened for activity in embryonic mesoderm and in specific mesodermal cell types. The results were validated by traditional reporter gene assay in Drosophila melanogaster embryos for 68 cCRMs tested by eFS. The specificity of eFS was excellent among significantly enriched cCRMs, while sensitivity was good where the majority of the CD2-positive cells express GFP. It was found that the known enhancer-associated chromatin marks H3K27ac, H3K4me1, and Pol II are significantly enriched among the enhancers found to be active in mesoderm.