Genotype management: Admin only delete all unused alleles?

[manulera]

@ValWood @kimrutherford

Sometimes genotype management is quite messy in CC. It would be nice to have an admin-only delete all unused genotypes to clear the session a bit. Definetely not a priority, but if it's an easy one I thikn it could be nice.

[ValWood]

In some sessions I did try to delete them. I think this is causing some of the problem where we get multiple alleles, so now I just leave them.

One reason to leave the unused single -allele mutants might be that the allele is then already present in the database if it is used in a subsequent paper (for entity recognition etc).