Coronoviruses are RNA viruses meaning that their genome is RNA, not DNA. All of the coronoviruses have similar genomes but I'm sure you are mostly interested in SARS-CoV-2, the virus that causes COVID-19. The first genome sequence of this virus was determined by Chinese scientists in early January and it was immediately posted on a public server. It came from a patient in intensive care at the Wuhan Yin-Tan Hospital (China). The paper was accepted on Jan. 20th and it appeared in the Feb. 3rd issue of Nature (Zhou et al. 2020).
By the time the paper came out several universities and pharmaceutical had already constructed potential therapeutics and several others had already cloned the genes and were preparing to publish the structures of the proteins.1
By now there are dozens and dozens of sequences of SARS-CoV-2 genomes from isolates in every part of the world. They are all very similar because the mutation rate in these RNA viruses is not high. The original isolate has a total length of 29,891 bp not counting the polyA tail. Note that these RNA viruses are about four times larger than a typical retrovirus.
The RNA genome that's inside the virus particle looks very much like a typical eukaryotic mRNA molecule. It has a 5′ cap and a 3′ polyA tail. This RNA is translated by the host protein synthesis components as soon as it is injected into the cell.
The genome contains a number of genes where the word "gene" is used to define the reading frame of the proteins produced by the virus. In several cases the initial translation product is a large polyprotein that is subsequently cleaved by a protease to produce smaller proteins.
Gene 1ab consist of two parts and two separate reading frames (1a and 1b). The two reading frames are not in phase but a frame-shift RNA structure located at their junction allows them to be translated into one very large polyprotein.
1. The behavior of Chinese scientists doesn't match with the conspiracy theory that China engineered this virus—perhaps they weren't in the loop?
