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.针对陆生蜗牛属（Cepaea）经典的壳色与条带多态性开展的研究，在确立自然选择对维持形态变异的重要性方面发挥了关键作用。Cepaea同时也是生态遗传学领域的杰出模型体系，因其体表颜色与条带表型完全由遗传决定，主要受至少包含5个基因座的超基因（supergene）调控。遗憾的是，针对Cepaea多态性的演化与维持机制的研究进展陷入停滞，部分原因在于缺乏可用的遗传标记。为重新将Cepaea确立为分子生态学的核心模型，我们开展了6组Cepaea nemoralis的实验室杂交实验，其中5组的杂交后代呈现壳底色（C）与条带有无（B）的性状分离。首先，对323个个体的颜色与条带表型进行分型后发现，该超基因的C与B基因座之间未发生重组。其次，通过对2个亲本与22个子代个体开展限制性酶切位点关联DNA测序（restriction site–associated DNA sequencing, RAD-Seq），我们鉴定出44个推定与壳底色（C）和条带（B）基因座连锁的匿名分子标记。我们在上述22个子代中对11个最具应用潜力的RAD-Seq标记的基因型进行了独立验证，随后又对多达146个子代个体完成了基因分型。已获得分型的最邻近RAD-Seq标记与C-B超基因连锁群的间距约为0.6厘摩（centimorgan, cM）；整合所有标记后，我们构建了一张覆盖Cepaea C-B超基因两侧、总长度为35.8 cM的连锁图谱。