Nanopore sequencing is a method of sequencing DNA and RNA. It is a technology which is positioned to replace (or supplement) sequencing using the polymerase chain reaction (PCR). (PCR was developed in the 1980s.) Nanopore sequencing is potentially cheaper than sequencing using PCR. Nanopore sequencing uses an electric field to move a sample through a nanopore, a pore of nanometer size. When the sample gets close enough to the nanopore, one can gather information about the sample by looking at changes in electric current density around the nanopore.