Overview of Ensembl Gene Build. Most genes are predicted using the sequences of known proteins aligned to the genome using genewise (Targetted and Similarity builds). UTR sequences for these genes are derived from the alignment of cDNAs to the genomic sequence (Exonerate, cDNA Gene Build). Transcripts created in this manner are then clustered to form genes (GeneBuilder). Finally, novel genes supported solely by cDNA evidence are added to the gene set, which is written to the database.