@srpearce From the help text, I think these lines of text sum it up pretty well:

Gene Explorer (GeneX) simulates the transcription, splicing, processing, and translation of a small hypothetical eukaryotic gene. GeneX will allow you to make specific mutations in a gene sequence, and it will then calculate and display their effects on the mRNA and protein. It will do all the tedious work of:
1. Finding the promoter and terminator
2. Reading the DNA sequence to produce the pre-mRNA
3. Finding the splice sites
4. Splicing and tailing the mRNA
5. Finding the start codon
6. Translating the mRNA