Tissue-specificity index (<i>τ</i>) calculations per gene, based on modENCODE anatomy RNA-Seq [34].

For each transcript, RPKM was downloaded from Flybase precomputed file, "gene_rpkm_report_fb_2018_05.tsv.gz". modENCODE tissues were grouped according to S6 Table, so that enrichment in any member of a given group was called as enrichment in that tissue group. All RPKM values were converted to log2(RPKM) in R, excluding 0 counts. log2(RPKM) is shown in each tissue column. log2(RPKM)< = 1 was considered not expressed. All transcripts that are not expressed in at least one tissue were coded as "Not Expressed". For each transcript, τ was calculated from log2-normalized RPKM values, as described in Yanai et al., 2005: where xi is the expression of a transcript in tissue i. Transcripts where τ<0.70 were called "Not enriched". Transcripts were considered enriched in a given tissue where τ> = 0.70 and expression in that tissue was greater than the cutoff (mean expression + 1.5 standard deviations). (XLSX)