PURPOSE OF REVIEW: SARS-CoV-2, the recently emerged coronavirus (CoV) that is 
responsible for the current global pandemic Covid-19, first appeared in late 
2019 in Wuhan, China. Here, we summarise details of the SARS-CoV-2 genome to 
assist understanding of the emergence, evolution and diagnosis of this deadly 
new virus.
RECENT FINDINGS: Based on high similarities in the genome sequences, the virus 
is thought to have arisen from SARS-like CoVs in bats but the lack of an 
intermediate species containing a CoV with even greater similarity has so far 
eluded discovery. The critical determinant of the SARS-CoV-2 genome is the spike 
(S) gene encoding the viral structural protein that interacts with the host cell 
entry receptor ACE2. The S protein is sufficiently adapted to bind human ACE2 
much more readily than SARS-CoV, the most closely related human CoV.
SUMMARY: Although the SARS-CoV-2 genome is undergoing subtle evolution in humans 
through mutation that may enhance transmission, there is limited evidence for 
attenuation that might weaken the virus. It is also still unclear as to the 
events that led to the virus' emergence from bats. Importantly, current 
diagnosis requires specific recognition and amplification of the SARS-CoV-2 RNA 
genome by qPCR, despite these ongoing viral genome changes. Alternative 
diagnostic procedures relying on immunoassay are becoming more prevalent.