The ~5.3 millions human EST sequences map to ~54,000 UniGene clusters [4,13]. Previously in [3] we calculated the gene expression pattern for each UniGene in 30 human tissues based on NCBI EST database. We identified 7261 tissue-specific genes for the 30 tissues based on the expression enrichment (EE) and statistical significance. On average, based on these definitions, each tissue expresses ~290 tissue-specific genes [3]. Figure 1A shows the expression profile for the eye-specific gene RPE65 (RefSeq ID: NM_000329; UniGene ID: Hs.2133; Ensembl ID: ENSG00000116745).
