B4
From each viral pool, 75 ng of viral DNA was sheared and ligated to adaptors by transposition using in-house prepared Tn5 enzyme (Picelli et al, Genome Research, 2014). Transposition was carried out for 10 min at 55C, after which sheared, adaptor-ligated templates were inactivated with SDS and transferred directly to a PCR reaction to amplify and add a library specific pair of 10-bp index sequences. Pooled libraries were sequenced on an Illumina HiSeq 4000 instrument (Illumina) using 150-bp forward and reverse reads.