Transcript truncation by PTCs. Distribution of the percent of transcript cDNA truncated by PTCs for all transcripts affected by computationally confirmed PTCs. Bars to the left represent less of the cDNA truncated (starting with the bin of 0% to 1% of the gene truncated) and bars to the right represent more of the cDNA truncated (ending with 99% to 100% truncated). Subsequently, bars to the left represent PTCs that occur towards the end of a gene, whereas bars to the right represent PTCs that occur towards the beginning of a gene. PTCs private to cave and surface populations did not have a significantly different distribution from one another.