title: Illumina HiSeq 4000 paired end sequencing
library_construction_protocol: genomic DNA was sheared on a Covaris LE220 (Covaris Woburn, Massachusetts, USA) in order to reach fragment sizes of ∼500 bp. The fragmented DNA was further size-selected for fragment sizes of 220-550 bp with AMPure XP beads (Agencourt, Beckman Coulter). The size-selected genomic DNA fragments were end-repaired, adenylated and ligated to Illumina sequencing compatible indexed paired-end adaptors (NEXTflex DNA Barcodes). The adaptor-modified end library was size-selected and purified with AMPure XP beads to eliminate any non-ligated adapters. The ligation product was split into three samples and in three separate reactions enriched with 12 PCR cycles and then validated on an Agilent 2100 Bioanalyzer with the DNA 7500 assay (Agilent) for size and quantity.