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.

针对陆地蜗牛 Cepaea（Cepaea）经典的外壳颜色与条纹多态性的研究，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。该属蜗牛同时也是生态遗传学领域的杰出模型生物，因其外壳颜色与条纹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，针对该属蜗牛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 确立为分子生态学领域的重要模型，我们开展了六组 Cepaea nemoralis（Cepaea nemoralis）的实验室杂交实验，其中五组针对外壳底色（C）与条纹有无（B）性状发生分离。首先，对323个个体的颜色与条纹性状进行分型后发现，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个子代个体进行限制性酶切位点关联DNA测序（restriction site–associated DNA sequencing, RAD-Seq），我们共鉴定出44个推测与颜色（C）和条纹（B）基因座连锁的匿名标记。我们在同一组22个子代个体中，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，随后又对最多146个子代个体进行了基因分型。所筛选到的距离C-B超基因连锁群最近的RAD-Seq标记，与其间距仅约0.6厘摩（centimorgan, cM）；联合这些标记构建的连锁图谱总长35.8 cM，且两侧均有标记锚定该属蜗牛C-B超基因区域。