Figure 7

Example effect of percentage filtering used to reduce the coverage of ambiguity codes. In the original nucleotide distribution for a specific position, the ambiguity code D, which represents A, G, or T is called. C is likely to be a result of sequencing error, so it is preferable to exclude it when designing degenerate primers. After applying a 5% filter, the assigned ambiguity code for that position can be reduced to a W, which more accurately represents the target population (A or T).