Fig. 4: Expression of ENaC-coding genes in Bottlenose dolphin (Tursiops truncatus) tissues.

A RT-PCRs were performed with cDNA synthesised from tissues derived from three animals. Arrow heads point towards the expected amplicon sizes. Numbers in parentheses indicate positive amplicons out of the total number of animals. PCR results from all animals are provided in ref. ²⁴. β-actin (ACTB) was used as controls. RT reverse tanscriptase, M = DNA size marker; bp base pairs. B Splicing profiles of SCNN1A, SCNN1B, SCNN1G, and SCNN1D in Tursiops truncatus skin tissue based on RNA-seq data (GEO: SRX7005031). Sashimi plots were generated using Integrative Genomics Viewer (IGV v2.19.2) from splice junction-aware RNA-seq alignments. A minimum of 30 supporting reads was set as the junction threshold for SCNN1A, SCNN1B, and SCNN1G, and a threshold of 2 reads for SCNN1D due to lower expression. Splice junctions are annotated with the number of supporting reads. PE denotes an out-of-frame pseudo-exon inclusion event observed in SCNN1D. An asterisk (*) marks a novel donor splice site (+7 nt) upstream of exon 6 in SCNN1D. Loss of predicted exon structure is observed in SCNN1D, suggesting either exon skipping or incomplete transcript assembly. Gene structure and exon numbering follow canonical annotations as also shown in Fig. 1.