Stop codons and exons? If we had a hypotheical gene called gene **_exampleGene_** and this gene had 5 exons, labeled **_A, B, C, D, and E_** in that order on the chromosome, could it be the case that the stop codon for this gene be on exon **_D_** and the exon **_E_** still being a exon that would be transcribed in? I can not see this to be true, since If I remember correctly, transcription stops BEFORE the stop codon, and when stopped, the pre-mRNA is then further processed, but everything after that stop would not be a part of the **_exampleGene_** ? My lazy diagram of how I think of the supposed **_exampleGene_** to be: \---A-----B---C---------D(stop codon)-------E--- After transcription via RNA polymerase: A-----B---C---------D

Take a look at this schematic of a mature mRNA.

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The coding region (ie the part that is translated) is between the start and stop codons, but the 5' and 3' untranslated regions (UTRs) are also transcribed by RNA polymerase; these are part of the first and last exons, respectively. The transcription start site is labelled right in front of the 5' UTR. For the purpose of this answer, transcription termination can be said to occur at the poly(A) signal (the poly(A) tail is added post-transcriptionally, as is the 5' cap).

To be clear, the point I'm hopefully making is that transcription does not involve codons. RNA polymerase does not stop at the stop codon nor does it start at the start codon. In fact, it doesn't even "know" what codons are.