The speed and error rate of DNA synthesis is influenced by the three-dimensional structure of the DNA. Using “third-generation” genome-wide DNA sequencing data, a team of researchers from Penn State and the Czech Academy of Sciences showed that sequences with the potential to form unusual DNA conformations, which are frequently associated with cancer and neurological diseases, can in fact slow down or speed up the DNA synthesis process and cause more or fewer sequencing errors. An article describing the study appears online in the journal Genome Research.