  We present an unique way to detect basepair mismatches in DNA leading to
different epigenetic disorder by the method of nanopore sequencing. Based on a
tight-binding formulation of graphene nanopore based device, using Greens
function approach we measure the changes in the electronic transport properties
of the device as we translocate a double-stranded DNA through the nanopore
embeded in a zigzag graphene nanoribbon. In the present work we not only
successfully detect the usual AT and GC pairs, but also a set of possible
mismatches in the complementary base-pairing without any ambiguity. Our
investigation shows that this device can also be used for reliable sequential
detection of other biomolecules.
