Genomic composition of downy birch (Betula pubescens)

Here, we sequenced 255 B. pubescens (downy birch) specimens collected from twenty-three locations along the species' range. We also sequenced four other members of the birch genus and a triploid hybrid. We use population-level exonic data to reconstruct the phylogenetic history of Betula pubescens, ), a tetraploid species known to hybridize with at least four other birch species. Our results provide new insights into the evolutionary origin of B. pubescens, its genomic composition, and the probable role of alleles introgressed from B. nana and B. humilis. Individual libraries were generated using Roche's SeqCap EZ HyperCapWorkflow using custom probes designed for targeted exome capture and sequenced on paired-end mode (150 bp) on an Illumina NovaSeq 6000 platform. Target resequencing was based on a custom probe design covering 1,609 nuclear genes with a 3.2M bp cumulative target size.