Mechanisms Behind the Formation of Ellipsoid Eggs in Silk-Worms (Bombyx mori): Insights from Transcriptomic Profiling

Background: /Objectives: The elongated egg is a morphological mutant of silkworm (Bombyx mori) eggs, yet the biochemical processes and molecular mechanisms underlying this trait remain unclear. Methods: In this study, we performed transcriptome sequencing on the ovaries of female pupae from the Nistari silkworm strain (comparing normal and elongated eggs) during the first three days post-pupation using high-throughput se-quencing. Results: A total of 153.56 Gb of filtered data was obtained, identifying 23,366 genes and 35,798 mRNAs. Comparative analysis across three control groups revealed 374 differentially expressed genes (DEGs), with 131 upregulated and 243 downregulated genes. GO and KEGG enrichment analyses indicated that these DEGs were primarily as-sociated with protein hydrolysis, DNA metabolic processes, and euchroma-tin/heterochromatin organization. Trend expression analysis revealed that transcriptional activity in elongated eggs was significantly higher than in normal eggs, particularly on day 3 of the pupal stage. Conclusions: WGCNA analysis classified gene expression pat-terns into twelve modules, with two modules showing specificity. Thirteen hub genes were identified, which are functionally linked to translation initiation, protein density regulation, post-translational modification, and protein turnover. These findings provide foundational insights into the molecular mechanisms driving the formation of elongated egg in silkworms.