Exons were grouped based on similar expression patterns and large RPGM differences from their neighboring exons. These groups showed increased or decreased expression in alcoholic brains as supported by RPJM changes. However, the expression changes seen with individual exon groups were apparently not large enough to change overall GABAB1 expression. The reasons include the possibility of transcript lengths that are much shorter than the whole GABAB1 gene. It is also due to the finding that some exons showed decreases in expression whereas others showed increases though exon GC content difference could affect the RPGM calculation. For all 23 GABAB1 exons, 9 exons increased, 2 exons decreased, and 12 exons did not change. This expression pattern probably prevented an overall GABAB1 expression change in alcoholic brains.
