Supplementary data items for Zilko et al (2021) 1.DArTseq genotypes and metadata. SNP genotype data in 2-row format with one row for each allele. Alleles are encoded as: 1=present, 0=absent, - = unscored. Metadata for each individual in the genotype dataset are also included. 2. Allele frequencies for Yellingbo and Lake Mountain. Vortex-formatted file with the first row indicating number of alleles at each locus (always 2), followed by total number of loci (1296). The first 1296 entries are allele frequencies for each locus at Yellingbo. The last 1296 entries are the allele frequencies for the same loci at Lake Mountain. 3. Studbook. Vortex-formatted file describing individuals alive at Yellingbo in 2019. 4. Kinships. Kinship matrix for living individuals in 2019 at Yellingbo. Values were calculated in the R package hierfstat then transformed to proportions by subtracting the smallest value from all entries.