Improved detection and size determination of VicTR-A repeats in Vicia narbonensis. EccDNA detection in V. narbonensis genomic DNA sample pre-treated with Plasmid-safe DNase and mung bean nuclease and resolved on 2-D electrophoresis using 0.7% and 2% agarose gels. Prior to electrophoresis, the sample was mixed with a set of circular DNA markers. The Southern blot of the gel was hybridized with VicTR-A probe (A), and then reprobed with the lambda DNA used to visualize DNA markers (B). Panel C shows superposition of signals from VicTR-A nad marker probes and gives the length of the open circle (OC), supercoiled (SC) and linear (L) markers (the lengths are in base pairs). VicTR-A signals on panel C are enhanced by longer exposure compared to panel A in order to reveal spots of the shortest circular molecules.