Methods and devices are provided for characterizing a duplex 
nucleic acid, e.g., a duplex 
DNA molecule. In the subject methods, a fluid conducting medium that includes a duplex 
nucleic acid molecule is contacted with a 
nanopore under the influence of an applied 
electric field and the resulting changes in current through the 
nanopore caused by the duplex 
nucleic acid molecule are monitored. The observed changes in current through the 
nanopore are then employed as a set of data values to characterize the duplex nucleic acid, where the set of data values may be employed in raw form or manipulated, e.g., into a current 
blockade profile. Also provided are nanopore devices for practicing the subject methods, where the subject nanopore devices are characterized by the presence of an 
algorithm which directs a 
processing means to employ monitored changes in current through a nanopore to characterize a duplex 
nucleic acid molecule responsible for the current changes. The subject methods and devices find use in a variety of applications, including, among other applications, the identification of an 
analyte duplex 
DNA molecule in a sample, the specific 
base sequence at a single nulceotide polymorphism (SNP), and the sequencing of duplex 
DNA molecules.