DArT-derived sex-linked SNPs for Macquarie perch and golden perch
Despite more biallelic SNP loci being yielded by DArTseq for Macquarie perch (6,939) compared to golden perch (5,997), Macquarie perch had an order of magnitude fewer sex-linked loci (4 vs 48) with lower proportion of individuals sharing a sex-specific allele (20% vs 30%; Table 2). Although this could just reflect lower genome-wide diversity of Macquarie perch, it may also suggest that sex chromosomes in Macquarie perch are younger than those in golden perch. Both species had loci with male-specific and female-specific alleles, with similar number of both types in Macquarie perch (2 and 2) but more female-specific alleles in golden perch (14 and 34, respectively). All sex-linked DArT SNPs were on different scaffolds, except two golden perch SNPs were on the same scaffold (Supplementary Material S2). Neither dataset revealed loci consistent with Y- linkage or XY- (or ZW-) gametologs, suggesting that sex chromosomes in both perch species evolved recently.