The life cycle of the holometabolous insect Bombyx mori (Linnaeus) consists of the embryo, larva, pupa, and adult stages with six larval molts. Ecdysone and juvenile hormones play important roles in the growth and development of the silkworms. The a42 silkworm mutant is recessive and homozygous lethal by exhibiting a dark‐colored and small body size and fails to molt to second instar. We compared the gene expression of a42 mutants with normal individuals at the first larval molting stage to elucidate the physiological influence of the a42 mutation on the growth and development of silkworms. The transcriptomic sequencing results revealed that 1,411 genes are differentially expressed in a42 mutants, compared with wild‐type control silkworms, in which 791 genes are upregulated and 620 genes are downregulated. Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analyses identified differentially expressed genes (DEGs) assigned to biological pathways, such as pentose and glucoronate interconversions, glycerolipid metabolism, folate biosynthesis, amino sugar, and nucleotide sugar metabolism. Two hydroxylases of phenylalanine hydroxylase (BmPAH) and tyrosine hydroxylase (BmTh) are upregulated in a42 mutants. The influence of a42 mutation on these DEGs reveals that melanin metabolism plays an important role during the molting process in silkworms.

中文翻译：

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非蜕变家蚕突变体（a42）的第一龄幼虫期的转录组学分析。

整体代谢昆虫家蚕（Linnaeus）的生命周期包括胚胎，幼虫，和成年阶段，其中有六个幼虫。蜕皮激素和少年激素在蚕的生长发育中起重要作用。的A42蚕突变是隐性的和纯合致死由呈现深色和小体型和未能蜕皮至第二龄期。我们在幼虫蜕皮的第一个阶段就将a42突变体的基因表达与正常个体进行了比较，以阐明a42突变对家蚕生长和发育的生理影响。转录组测序结果显示，a42基因差异表达了1,411个基因与野生型对照蚕相比，这些突变体中有791个基因被上调，而620个基因被下调。基因本体论/基因和基因组京都百科全书分析确定了与生物途径相关的差异表达基因（DEG），例如戊糖和葡萄糖酸互变，甘油脂代谢，叶酸生物合成，氨基糖和核苷酸糖代谢。在a42突变体中，苯丙氨酸羟化酶（BmPAH）和酪氨酸羟化酶（BmTh）的两种羟化酶上调。a42突变对这些DEG的影响表明，黑色素代谢在蚕蜕皮过程中起着重要作用。