Libraries described as 'Broad PCR-free' were prepared utilizing the protocol described as 'low-input Fisher et al. modified with Kapa Biosystems reagents' but with several modifications. The PCR-free protocol eliminates all of the amplification steps of the Fisher et al. protocol. Genomic DNA input into shearing was increased from 100 ng to 500 ng in 50 µl volume. Samples were sheared to an average fragment size of 200 bp instead of 150 bp. For adapter ligation, Illumina TruSeq Adapters (Illumina, CA, catalog FC-121-2001) were used instead of those described in Fisher et al.
