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.