Genetic basis of stage-specific melanism: a putative role for a cysteine sulfinic acid decarboxylase in insect pigmentation

Melanism, the overall darkening of the body, is a widespread form of animal adaptation to particular environments, and includes bookcase examples of evolution by natural selection, such as industrial melanism in the peppered moth. The major components of the melanin biosynthesis pathway have been characterized in model insects, but little is known about the genetic basis of life-stage specific melanism such as cases described in some lepidopteran species. Here, we investigate two melanic mutations of Bicyclus anynana butterflies, called Chocolate and melanine, that exclusively affect pigmentation of the larval and adult stages, respectively. Our analysis of Mendelian segregation patterns reveals that the larval and adult melanic phenotypes are due to alleles at different, independently segregating loci. Our linkage mapping analysis excludes the pigmentation candidate gene black as the melanine locus, and implicates the gene encoding a putative PLP-dependant cysteine sulfinic acid decarb...

黑色素沉着（Melanism）是指身体整体颜色加深的现象，是动物对特定环境的一种广泛适应形式，其中包含自然选择驱动进化的经典案例，例如桦尺蛾的工业性黑化。黑色素生物合成途径的主要成分已在模式昆虫中得到表征，但对于特定生活史阶段的黑色素沉着（如部分鳞翅目物种中描述的案例）的遗传基础，人们知之甚少。在此，我们研究了安纳米闪蝶（Bicyclus anynana）的两种黑化突变体——分别名为Chocolate和melanine，它们仅影响幼虫期和成虫期的色素沉着。孟德尔分离模式分析表明，幼虫期和成虫期的黑化表型分别由不同且独立分离的基因座上的等位基因导致。连锁图谱分析排除了色素沉着候选基因black作为melanine基因座的可能性，并提示编码假定的吡哆醛磷酸（PLP）依赖性半胱氨酸亚磺酸脱羧酶的基因可能参与其中...