Fig. 1: sQTL example.

a Relative abundances of the three most expressed isoforms in the brain cortex from the gene RBM23 (chr14:23,369,854-23,388,393, reverse strand, RBM23-001, RBM23-002 and RBM23-003, all protein coding), for each genotype group at the rs2295682 locus (chr14:23,374,862, G/A in the reverse strand), represented as boxplots. RBM23 encodes for an RBP that may be itself involved in splicing. The least abundant isoforms are grouped in Others. The number of individuals in each genotype group is shown between parentheses. Individuals that are homozygous for the reference allele (GG) at the SNP locus, express preferentially RBM23-002 (blue), while they barely express RBM23-003 (red). In contrast, AA homozygous express preferentially RBM23-003 (red). Heterozygous individuals exhibit intermediate abundances. RBM23-001 (green) has similar levels in the three genotype groups. In boxplots, the box represents the first to third quartiles and the median, while the whiskers indicate ± 1.5 × interquartile range (IQR). Source data are provided as a Source Data file. b Exonic structure of the isoforms of RBM23. Compared to RBM23-001 (green), RBM23-002 (blue) lacks exon 6, and RBM23-003 (red), exons 4 and 6. A sashimi plot corresponding to the highlighted area displays the mean exon inclusion of exon 6 of RBM23 across all brain cortex samples of each genotype group at rs2295682. The plot was obtained using ggsashimi⁸⁶. The dotted vertical line marks the location of the SNP. The number of reads supporting exon skipping increases with the number of copies of the alternative allele A, matching the changes observed in isoform abundances. This allele has been previously associated with increased skipping of exon 6⁸⁷.