ABSTRACT
The genome exhibits a signicant strand asymmetry and the coding capacity is about 90.5%, resultant in a total of 1262 putative open reading frames (ORFs), of which 911 encode proteins and 298 have a functional aspect (Genbank accession number NC_006450). Of these ORFs, the 80% have no known homologs, so they are called orphan genes. However, transcripts of some of these orphan genes have been detected within the viral particles, suggesting that at least part of these genes might encode for proteins useful to the Mimivirus replication cycle, but this is yet under investigation [5]. A set of 31 core genes, divided into four classes, is present in all or most members of NCLDV families [10], among which there are nine class I genes (that are conserved in all families), eight class II genes (that are conserved in all families, but missing in some species), 14 class III genes (that are conserved in three of four families), and 30 class IV genes (that are found only in two clades).
