I have a bunch of sequence files fetched from the EBI ENA and I'm trying to find the end of the 5' UTR for specific genes.
The UTR itself doesn't seem to be annotated in most sequence files I have. My original idea was to simply use the CDS annotations, as the start of those should clearly identify the end of the 5' UTR. But I also noticed gene annotations in many of the sequences, most of them starting and ending at exactly the same locations as the corresponding CDS annotation. But there are also cases where there are small differences between the gene and the CDS annotation.
So I'm wondering how exactly the gene annotation is defined (if there is actually an agreed definition) and how the gene and CDS annotations are used in practice.
Which annotation would be the most reliable to identify the end of the 5' UTR?