Fig. 1: Identification framework, distribution patterns, and sequence features of new genes in spiders.

a Gene classification into different PS levels on the basis of an organized workflow. b The 16 PS levels of T. clavata, spanning from the genes of the most ancient cellular organisms to the most recent species-specific genes. RAGs refer to relatively ancient genes, while RYGs refer to relatively young genes. c Gene number distribution across the 16 PS levels in T. clavata. The Venn diagram in the lower-right corner shows that genes from PS13 to PS16 are annotated as genes of unknown function. d–f Box plots showing the transition of genes across the 16 PS levels from ancient to young genes, with decreases in the exon length and protein sequence length, and an increase in the Tau index. The Tau index measures the specificity or breadth of gene or transcript expression across analyzed tissues. The gene sets analyzed for each PS level (PS1–PS16) in d–f are identical to those quantified in c. Box plots display the median (center line), the 25th and 75th percentiles (box limits), and the minimum and maximum values within 1.5× the interquartile range (whiskers).