University of Zurich researchers noticed brightness variations in low-energy electron images of DNA, as illustrated in this cartoon, which turned out to be a visualization of electric charge. Schematics of the low-energy electron microscope. These images, the first pictures of charge transport in DNA, were captured by an electron microscope at the University of Zurich. Studies have examined double-stranded DNA, single-stranded DNA, and DNA molecules under different conditions, but the results don’t seem to converge. The Andregg brothers had prepared the samples, but didn’t have a microscope with high enough resolution to verify that the DNA samples turned out as intended.