Fig. 4From: Selective forces and mutational biases drive stop codon usage in the human genome: a comparison with sense codon usageChange of stop codon fractions with the breadth of transcription. Transcriptome data were obtained from the Gene Expression Barcode (Barcode) database. Genes were clustered into four categories by proportion of cell types in which a gene was estimated as expressed (Pr). Values represent mean ± SEMBack to article page