Sequence Identifiers Associated with Entrez Gene ids in the ArrayGene database. The mRNA, genomic, and protein classes represent GenBank accession numbers that have been associated with an Entrez Gene by NCBI. RefSeq groups reference mRNAs, genomic and protein sequences. Ensembl transcript are ids from Ensembl. Unigene, symbol, and synonym are gene identifications than have been cross-referenced with an Entrez Gene id by NCBI. Unigene link are sequence accession numbers that have been clustered into Unigene ids that are associated with Entrez Genes. NIA transcripts represent ids of transcripts from the National Institute of Aging mouse Gene Index (V. 4.0) .