CodingSequence: The range of the coding sequence for this transcript, if any. To determine the exact ranges of coding sequence, intersect this range with those of the exons, if any. If there are any exons, the codingSequence must start and end within them.
Note that in some cases, the reference genome will not exactly match the observed mRNA transcript e.g. due to variance in the source genome from reference. In these cases, exon.frame will not necessarily match the expected reference reading frame and coding exon reference bases cannot necessarily be concatenated to produce the original transcript mRNA.