reduce the number of unmapped entrys due to priority xrefs being add several times
reduce the number of unmapped entrys due to priority xrefs being add several times

danstaines/ensembl,mjg17/ensembl,at7/ensembl,at7/ensembl,danstaines/ensembl,muffato/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,at7/ensembl,Ensembl/ensembl,willmclaren/ensembl,Ensembl/ensembl,Ensembl/ensembl,mjg17/ensembl,muffato/ensembl,muffato/ensembl,james-monkeyshines/ensembl,willmclaren/ensembl,at7/ensembl,muffato/ensembl,james-monkeyshines/ensembl,mjg17/ensembl,danstaines/ensembl,mjg17/ensembl