Fig. 4

Differential expression analysis and identification of sex-biased lncRNAs. a Hierarchical clustering heat map showing the expression profile of C. pomonella lncRNAs across seven different tissues and developmental stages. Apparently, the expression profile of lncRNAs exhibits a tissue-specific pattern. Abbreviations are listed as follows: Ag, accessory gland; Ma, male antennae; Fa, female antennae; Tes, testis; Ov, ovary; Mhd, male head; Fhd, female head; Mmg, male midgut; Fmg, female midgut; E1, egg day 1; E4, egg day 4; L5, 5th-instar larva; FP, female pupa; AF, adult female. b Volcano plots showing differentially expressed genes in sex-matched tissue samples. As shown in the figure, there was no significant difference in expression between males and females in the head, midgut, and antenna samples, and only a few genes were found to be differentially expressed between the male and female samples. By contrast, a large number of genes were found to be differentially expressed between the testis and ovary, suggesting a large difference in expression between the testis and ovary. Remarkably, many more lncRNAs were upregulated in the testis than in the ovary