To determine which types of transcripts are enriched in the top 200 P-value comparisons, a DAVID Gene Ontology (GO) analysis was performed on the associated gene IDs for each treatment: 167 air, 175 odor, 175, ethanol, and 188 trained genes. Using default DAVID settings, the top three GO annotations were identified (Figure S6). Compared to air controls, repeated ethanol exposures produced statistically significant GO terms: “Alternative splicing” (P-value = 0.0002), “Phosphoprotein” (P-value = 0.041), and “Coiled Coil” (P-value = 0.047). Interestingly, the response to trained treatment also produced “Alternative splicing” (P-value = 0.062) as a high-scoring enrichment category. It is important to note that the “Alternative splicing” GO term does not refer to spliceosome genes, but rather to genes that are “known to be alternatively spliced.” The enrichment analysis results further support the idea that there are experience-dependent changes in transcript usage, but not overall gene-level changes. Optimally, future ontology databases will include transcript-specific functional categorization.
