Genomic structures and taxonomic classification

Comparably, MERS-CoV encodes five unique accessory genes, designated   ORF3, ORF4a, ORF4b, ORF5 and ORF8b. None of these genes have been shown to be related to other known coronavirus genes at the time of discovery. MERS-CoV was found to have 75 and 77% amino acid sequence identity in 7 conserved replicase genes with two previously identified bat coronaviruses: BtCoV-HKU4 and BtCoV-HKU5