School of Life Sciences, University Park, University of Nottingham, Nottingham, NG7 2RD, UK.
Evolutionary Ecology, Naturalis Biodiversity Center, Leiden, 2333CR, The Netherlands.
Heredity (Edinb). 2023 Dec;131(5-6):327-337. doi: 10.1038/s41437-023-00648-z. Epub 2023 Sep 27.
Molluscs are a highly speciose phylum that exhibits an astonishing array of colours and patterns, yet relatively little progress has been made in identifying the underlying genes that determine phenotypic variation. One prominent example is the land snail Cepaea nemoralis for which classical genetic studies have shown that around nine loci, several physically linked and inherited together as a 'supergene', control the shell colour and banding polymorphism. As a first step towards identifying the genes involved, we used whole-genome resequencing of individuals from a laboratory cross to construct a high-density linkage map, and then trait mapping to identify 95% confidence intervals for the chromosomal region that contains the supergene, specifically the colour locus (C), and the unlinked mid-banded locus (U). The linkage map is made up of 215,593 markers, ordered into 22 linkage groups, with one large group making up ~27% of the genome. The C locus was mapped to a ~1.3 cM region on linkage group 11, and the U locus was mapped to a ~0.7 cM region on linkage group 15. The linkage map will serve as an important resource for further evolutionary and population genomic studies of C. nemoralis and related species, as well as the identification of candidate genes within the supergene and for the mid-banding phenotype.
软体动物是一门高度特异的门，展示出令人惊讶的各种颜色和图案，但在确定决定表型变异的潜在基因方面，相对进展甚微。一个突出的例子是陆地蜗牛 Cepaea nemoralis，经典的遗传研究表明，大约有九个基因座，其中几个物理上连锁并作为一个“超级基因座”一起遗传，控制着壳的颜色和带斑多态性。作为鉴定相关基因的第一步，我们使用来自实验室杂交个体的全基因组重测序构建了高密度连锁图谱，然后进行性状图谱分析，以确定包含超级基因座（即颜色基因座（C）和非连锁的中带基因座（U）的染色体区域的 95%置信区间。连锁图谱由 215593 个标记组成，有序排列成 22 个连锁群，其中一个大群约占基因组的 27%。C 基因座被定位到连锁群 11 上约 1.3 cM 的区域，U 基因座被定位到连锁群 15 上约 0.7 cM 的区域。连锁图谱将作为进一步研究 Cepaea nemoralis 和相关物种的进化和群体基因组学的重要资源，以及鉴定超级基因座和中带表型内的候选基因的重要资源。
