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Is it possible to make VariantAnnotator check REF and ALT fields?
Hi! So we use GATK a lot in our research, it works amazingly well most of the time, so first of all, thanks for creating it!
We have this one problem that we were unable to solve on our own. Say we have a VCF file that contains called variants, and we want to annotate it using an external database, clinvar as one example. We used to use VariantAnnotator for this purpose until we found out (both by reading documentation and doing a quick experimental check) that it annotates variants based solely on position, ignoring the actual mutation that happened. Imagine for example that variant A → C was called at a specific position, but data for A → G is recorded at clinvar. In this case VariantAnnotator will still carry over INFO fields from clinvar into our VCF. We ideally do not want this to happen, because strictly speaking clinvar data was recorded for a completely different mutation and might not be relevant at all in our case.
My question: is there an option for VariantAnnotator to make it check REF and ALT fields in the process of annotation? (Although I fear it wouldn't be possible because it uses RodWalker class to traverse the variants.) Or, alternatively, can this be achieved using combination of other GATK commands? Or will we have to write a custom walker to accomplish what we want? (The latter is obviously the worst case, but hopefully we can manage that.)
All the best,