To account for sequencing errors, we adjust the construction of the read graph to allow for mismatches. We use three parameters: (1) n = #mismatches allowed between a read and a superread, (2) m = #mismatches allowed in the overlap between two adjacent reads, and (3) t = #mismatches expected between a read and a random quasispecies. The probability that two reads u and v with j mismatches within an overlap of length o = e(u) b(v) belong to the same quasispecies can be estimated as: