The expression levels of some intrinsic genes, protease activity, and regulation of signaling pathways were distinct during different growth and development stages in the silkworm, Bombyx mori. The silkworm mutant mini was discovered from the normal silkworm strain S8V, and the body‐size of the mini mutant was smaller than the wild‐type from the second‐instar and the difference became more significant in the following stages. In this study, genetic analysis of mini mutant showed that mini mutant was controlled by a single recessive gene, manifested as homozygous lethal. Then, the transcriptome analysis of the mini mutant indicated that 2944 differentially expressed genes (DEGs) were identified from the silkworm in the 48 h of the second‐instar, of which 1638 genes in the mini mutants were upregulated and 1306 genes were downregulated. These DEGs were mainly distributed in the biological process, cellular component, and molecular function. The functional annotation based on the KEGG database showed that these genes were mainly clustered in metabolic pathways, fatty acid metabolism pathways, ribosome biogenesis in eukaryotes, and so on. Further analysis indicated that some genes involved in the growth and metabolism including enzyme genes, juvenile hormone, and ecdysone exhibited different transcriptional levels. These results provided new experimental evidence regarding the mechanism of the underlying formation of mini mutants.

中文翻译：

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家蚕微型突变体的遗传分析和转录组分析

家蚕在不同的生长发育阶段，一些内在基因的表达水平，蛋白酶活性和信号传导途径的调控是不同的。mini蚕突变体是从正常的S8V蚕菌株中发现的，  mini突变体的体型小于第二龄幼虫的野生型，其差异在随后的阶段变得更加显着。在这项研究中，对微型突变体的遗传分析表明，微型突变体受单个隐性基因控制，表现为纯合致死性。然后，迷你的转录组分析该突变体表明，在第二龄幼虫的48小时内从家蚕中鉴定出2944个差异表达基因（DEG），其中迷你突变体中的1638个基因被上调，而1306个基因被下调。这些DEG主要分布在生物过程，细胞成分和分子功能中。基于KEGG数据库的功能注释表明，这些基因主要聚集在代谢途径，脂肪酸代谢途径，真核生物中的核糖体生物发生等方面。进一步的分析表明，一些参与生长和代谢的基因，包括酶基因，少年激素和蜕皮激素，表现出不同的转录水平。这些结果提供了新的实验证据，有关潜在的形成机制迷你突变体。