Data from: Genetic architectures of postmating isolation and morphology of two highly diverged rockfishes (genus Sebastes)

Postmating isolation is thought to be an important driver of the late
stages of speciation. However, relatively little is empirically known
about the process compared to other isolating mechanisms that drive the
early stages of speciation, especially in non-model organisms. We
characterized the genetic architecture of postmating isolation between two
rockfishes, Sebastes schlegelii and S. trivittatus, whose reproductive
isolation is complete. We examined transmission ratio distortion (TRD)
patterns of genetic markers in two reciprocal backcross populations.
Markers showing either of the two types of TRD was widespread across the
genome, with some of the distorted markers forming extensive clusters
around the recombination coldspots. These suggest that the postmating
isolation effectively prevents gene flow across the genome and the
recombination landscape contributes to the genetic architecture.
Comparisons between two backcross families and two developmental stages
showed little similarity in the distorted markers, suggesting asymmetry
and stage-specificity of the isolation. This may be due to hybrid
incompatibility involving maternal factors or extrinsic selection. The
lack of sex-ratio distortion in the mapping families suggested that
Haldane's rule in terms of hybrid inviability does not hold.
Additionally, QTL mapping detected significant QTLs for sex and the
morphological traits relevant to speciation and convergence of rockfishes,
including body coloration. Genes in the melanocortin system, including
agouti-signaling protein 1 (asip1) and melanocortin 1 receptor (mc1r),
might underlie the horizontal and vertical color patterns on the body,
respectively. These findings constitute an essential step towards a
comprehensive understanding of speciation and morphological
diversification of rockfishes.