Data from: RAD-mapping reveals an evolving, polymorphic and fuzzy boundary of a plant pseudoautosomal region

How loss of genetic exchanges (recombination) evolves between sex
chromosomes is a long-standing question. Suppressed recombination may
evolve when a sexually antagonistic (SA) polymorphism occurs in a
partially sex-linked, “pseudo-autosomal’ region (or “PAR”), maintaining
allele frequency differences between the two sexes, and creating selection
for closer linkage with the fully sex-linked region of the Y chromosome in
XY systems, or the W in ZW sex chromosome systems. Most evidence
consistent with the SA polymorphism hypothesis is currently indirect, and
more studies of the genetics and population genetics of PAR genes are
clearly needed. The sex chromosomes of the plant Silene latifolia are
suitable for such studies, as they evolved recently and the loss of
recombination could still be ongoing. Here, we used RAD sequencing to
genetically map sequences in this plant, which has a large genome (~ 3
gigabases) and no available whole genome sequence. We mapped 83 genes on
the sex chromosomes, and comparative mapping in the related species S.
vulgaris supports previous evidence for additions to an ancestral PAR, and
identified at least 12 PAR genes. We describe evidence that recombination
rates have been reduced in meiosis of both sexes, and differences in
recombination between S. latifolia families suggest ongoing recombination
suppression. Large allele frequency differences between the sexes were
found at several loci closely linked to the PAR boundary, and genes in
different regions of the PAR showed striking sequence diversity patterns
that help illuminate the evolution of the PAR.