code: def mutateSequence(seq, distance):
      
      subProb=distance
      inProb=0.05*distance
      deProb=0.05*distance
      contProb=0.9
      l = []
      bases = [ 'A', 'C', 'T', 'G' ]
      i=0
      while i < len(seq):
          if random.random() < subProb:
              l.append(random.choice(bases))
          else:
              l.append(seq[i])
          if random.random() < inProb:
              l += getRandomSequence(_expLength(0, contProb))[1]
          if random.random() < deProb:
              i += int(_expLength(0, contProb))
          i += 1
      return "".join(l)
docs: Mutates the DNA sequence for use in testing.