How it works

Trimming of each type of homopolymer at each read end is done in the same way.

Using polyG as an example:

The window then slides by one position, to cover 9 of the original bases and 1 additional base, and the steps decribed above are repeated.

This process continues until the sliding 10-base window contains fewer than 9 Gs. At that point, checking stops and all bases marked to be trimmed are removed.

Examples of the effects of trimming particular sequences: