Data from: Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

We have constructed a linkage map for the peppered moth (Biston betularia), the classical ecological genetics model of industrial melanism, aimed both at localizing the network of loci controlling melanism and making inferences about chromosome dynamics. The linkage map, which is based primarily on amplified fragment length polymorphisms (AFLPs) and genes, consists of 31 linkage groups (LGs; consistent with the karyotype). Comparison with the evolutionarily distant Bombyx mori suggests that the gene content of chromosomes is highly conserved. Gene order is conserved on the autosomes, but noticeably less so on the Z chromosome, as confirmed by physical mapping using bacterial artificial chromosome fluorescence in situ hybridization (BAC-FISH). Synteny mapping identified three pairs of B. betularia LGs (11/29, 23/30 and 24/31) as being orthologous to three B. mori chromosomes (11, 23 and 24, respectively). A similar finding in an outgroup moth (Plutella xylostella) indicates that the B. mori karyotype (n=28) is a phylogenetically derived state resulting from three chromosome fusions. As with other Lepidoptera, the B. betularia W chromosome consists largely of repetitive sequence, but exceptionally we found a W homolog of a Z-linked gene (laminin A), possibly resulting from ectopic recombination between the sex chromosomes. The B. betularia linkage map, featuring the network of known melanization genes, serves as a resource for melanism research in Lepidoptera. Moreover, its close resemblance to the ancestral lepidopteran karyotype (n=31) makes it a useful reference point for reconstructing chromosome dynamic events and ancestral genome architectures. Our study highlights the unusual evolutionary stability of lepidopteran autosomes; in contrast, higher rates of intrachromosomal rearrangements support a special role of the Z chromosome in adaptive evolution and speciation.

我们针对工业黑化现象的经典生态遗传模型物种——桦尺蛾（peppered moth, *Biston betularia*）构建了一套连锁图谱，该图谱旨在定位控制黑化性状的基因座网络，并推断染色体动态变化。
该连锁图谱主要基于扩增片段长度多态性（amplified fragment length polymorphisms, AFLP）和基因构建，共包含31个连锁群（linkage groups, LGs），这与桦尺蛾的核型一致。
通过与进化距离较远的家蚕（*Bombyx mori*）进行比较，结果表明染色体的基因组成具有高度保守性。常染色体上的基因顺序较为保守，但Z染色体上的保守性显著降低，这一结论通过细菌人工染色体荧光原位杂交（bacterial artificial chromosome fluorescence in situ hybridization, BAC-FISH）进行物理图谱分析得到了验证。
同线性分析结果显示，桦尺蛾的3对连锁群（11/29、23/30和24/31）分别与家蚕的3条染色体（11、23和24号）为直系同源关系。在外群类群小菜蛾（*Plutella xylostella*）中得到的相似结果表明，家蚕的核型（n=28）是经由3次染色体融合演化而来的系统发育衍生状态。
与其他鳞翅目昆虫类似，桦尺蛾的W染色体主要由重复序列构成，但我们意外发现了一个Z连锁基因——层粘连蛋白A（laminin A）的W同源基因，这可能是性染色体之间发生异位重组的结果。
这套涵盖已知黑化相关基因网络的桦尺蛾连锁图谱，可作为鳞翅目黑化研究的重要资源。此外，该图谱与鳞翅目祖先核型（n=31）高度相似，使其成为重建染色体动态变化事件与祖先基因组结构的可靠参考。
本研究凸显了鳞翅目常染色体非同寻常的进化稳定性；与之形成对比的是，更高的染色体内重排速率佐证了Z染色体在适应性进化与物种形成过程中的特殊作用。