Data from: RAD-Seq derived markers flank the shell colour and banding loci of the Cepaea nemoralis supergene

Studies on the classic shell colour and banding polymorphism of the land
snail Cepaea played a crucial role in establishing the importance of
natural selection in maintaining morphological variation. Cepaea is also a
pre-eminent model for ecological genetics because the outward colour and
banding phenotype is entirely genetically determined, primarily by a
‘supergene’ of at least five loci. Unfortunately, progress in
understanding the evolution and maintenance of the Cepaea polymorphism
stalled, partly because of a lack of genetic markers. With a view to
re-establish Cepaea as a prominent model of molecular ecology, we made six
laboratory crosses of Cepaea nemoralis, five of which segregated for shell
ground colour (C) and the presence or absence of bands (B). First, scoring
of colour and banding in 323 individuals found no recombination between
the C and B loci of the supergene. Second, using restriction
site–associated DNA sequencing (RAD-Seq) of two parents and 22 offspring,
we identified 44 anonymous markers putatively linked to the colour (C) and
banding (B) loci. The genotype of eleven of the most promising RAD-Seq
markers was independently validated in the same 22 offspring, then up to a
further 146 offspring were genotyped. The closest RAD-Seq markers scored
are within ~0.6 centimorgan (cM) of the C-B supergene linkage group, with
the combined loci together forming a 35.8 cM linkage map of markers that
flank both sides of the Cepaea C-B supergene.