Data from: Advances in finding Alba: the locus affecting life history and color polymorphism in a Colias butterfly

Although alternative life history strategies exist within many populations, very little is known about their genetic basis and mechanistic insight to these traits could greatly advance the understanding of eco-evolutionary dynamics. Many species of butterfly within the genus Colias exhibit a sex-limited wing color polymorphism, called Alba, which is correlated with an alternative life history strategy. Here we have taken the first steps in localizing the region carrying Alba in Colias croceus, a species with no genomic resources, by generating whole genome sequence of a single Alba mother and two sequencing pools, one for her Alba, and another for her orange, offspring. These data were used in a bulk segregant analysis wherein SNPs fulfilling the Mendelian inheritance expectations of Alba were identified. Then, using the conserved synteny in Lepidoptera, the Alba locus was assigned to chromosome 15 in Bombyx mori. We then identified candidate regions within the chromosome by investigating the distribution of Alba SNPs along the chromosome and the difference in nucleotide diversity in exons between the two pools. A region spanning ~5.7 Mbp at the 5’ end of the chromosome was identified as likely to contain the Alba locus. These insights set the stage for more detailed genomic scans and mapping of the Alba phenotype and demonstrate an efficient use of genomic resources in a novel species.

尽管诸多种群中均存在替代生活史策略，但目前对其遗传基础的认知仍极为有限；而对这些性状的机制解析，将极大推动生态-进化动力学（eco-evolutionary dynamics）领域的研究进展。豆粉蝶属（Colias）的多个蝴蝶物种均存在一种被称为Alba的性限翅色多态现象，该性状与替代生活史策略密切相关。本研究以缺乏基因组资源的橙黄豆粉蝶（Colias croceus）为研究对象，率先开展了其Alba位点的定位工作：通过对单只Alba表型雌虫进行全基因组测序，并构建两个子代测序混池——分别对应Alba表型与橙色表型的子代——获取测序数据。利用上述数据开展集群分离分析（bulk segregant analysis），筛选出符合Alba性状孟德尔遗传预期的单核苷酸多态性位点（SNPs，single nucleotide polymorphism）。随后，借助鳞翅目昆虫保守的同线性（synteny），我们将Alba位点定位至家蚕（Bombyx mori）的15号染色体。我们进一步通过分析Alba相关SNPs在染色体上的分布特征，以及两个混池外显子区域的核苷酸多样性差异，定位到该染色体上的候选区域。最终在该染色体的5’端鉴定出一段长度约5.7兆碱基对（Mbp）的区域，推测该区域携带Alba位点。本研究的发现为Alba表型的精细化基因组扫描与定位研究奠定了基础，同时证明了在无基因组资源的非模式物种中高效利用基因组测序数据的可行性。