// specific use case:
// Genomic contig ENSCHR:1, contains coding regions for ENSG01,
// ENSG02, ENSG03, with transcripts and products similarly named.
// cannot add distinct dbrefs mapping location on ENSCHR:1 to ENSG01
// specific use case:
// Genomic contig ENSCHR:1, contains coding regions for ENSG01,
// ENSG02, ENSG03, with transcripts and products similarly named.
// cannot add distinct dbrefs mapping location on ENSCHR:1 to ENSG01