The document evaluates two methods for fragmenting DNA for Illumina sequencing library preparation: nebulization and shearing using the Bioruptor. It finds that the Bioruptor provides a more uniform size range compared to nebulization, with more DNA sheared to the relevant 200-500bp size range. The Bioruptor can also process multiple samples in parallel, is easier to use, and reduces risks of contamination compared to nebulization. Based on these results, the lab now uses the Bioruptor for its standard Illumina library construction protocol.