Distribution of errors along sequences. The blue line indicates the proportion of generated sequences (y-axis) as a function of sequence position (x-axis), based on data obtained from the analysis of reference sequence #3. The error rate for each type of error (insertions, deletions, mismatches and ambiguous base calls) is presented as a function of sequence position (X-axis) and specific position on the y axis. The position and length of homopolymers for each base are given on the x-axis to facilitate interpretation (green: A, red: T, black: G, blue: C). See additional file 2 for the data obtained with the other five reference sequences.