 <unk> = <unk> . Note , however , that most databases have their own numbering system , e.g. the EcoGene database uses <unk> for recD . Finally , ECK numbers are specifically used for alleles in the MG1655 strain of E. coli K @-@ 12 . Complete lists of genes and their synonyms can be obtained from databases such as EcoGene or <unk> . 
