Evolutional insights on uncharacterized SARS coronavirus genes

The complete genome of the severe acute respiratory syndrome coronavirus (SARS‐CoV) and many of its variants has been determined by several laboratories. The genome contains fourteen predicted open reading frames (ORFs). However, a function had been clearly assigned for only six of these ORFs, in the viral replication, transcription and structural constituents. The others are herein referred to as uncharacterized ORFs (UC‐ORFs). Here, we try to provide a relational insight on those UC‐ORFs, suggesting that a number of them are remotely related to structural proteins of coronaviruses and other viruses infecting mammalian hosts. Surprisingly, several of the UC‐ORFs exhibit considerable similarity with other SARS‐CoV ORFs. These observations may provide clues on the evolution and genome dynamics of the SARS‐CoV.