Figure 3. Quality controls of the final libraries by Bioanalyzer.

A. Example of a good library with the major peak between 200 bp and 300 bp, no significant peak is observed at a lower size. B. Example of a library containing primer dimers (significant peak at ~75 bp and/or 150 bp). For this sample, a second bead clean-up (with 1x ratio of beads) would have to be performed to remove the primer dimers before sequencing the library.