library_construction_protocol: genomic DNA isolated using the QIAamp DNA Blood Maxi Kit (Qiagen, Manchester, UK). The library was produced using forward and reverse barcode primers and the NEBNext High Fidelity PCR Master Mix (New England Biolabs, Hitchin, UK) according to previously published protocols (Joung et al 2017, Nature Protocols, 12(4):828-863. doi: 10.1038/nprot.2017.016) and pooled PCR products purified using the QIAquick PCR Purification Kit (Qiagen).