Figure 1.

Splicing- and Position-Dependent Patterns of Nucleotide Composition in Human Genes

(A) GC4 distribution of human protein-coding genes, grouped by number of exons per gene. The y axis indicates the proportion of genes within a given range of GC4.

(B) Mean GC4 content in protein-coding exons, grouped by exon position (rank) and by number of exons per gene.

(C) Mean GC4 for individual codons within exons of rank 1 (black dots) or rank 2 (white dots) downstream of the TSS.

(D) GC4 distribution of functional retrogenes (dark gray) and their corresponding parental genes (light gray) conserved between mouse and human (p = 2.1 × 10⁻⁴, from one-tailed Wilcoxon signed-rank test, n = 49).

See also Figure S1.