Back in January 2020, I wrote about a deletion that appeared in the genome of SARS-CoVÂ during the middle and late phase of the epidemic (link to article). A similar deletion has now been detected in the genome of SARS-CoV-2 (link to article).
The deletion in the SARS-CoV genome occurred in a region encoding a protein called Orf8.Â It was initially suggested that the 29 nucleotide deletion was somehow involved in adaptation of SARS-CoV to humans. This hypothesis was disproven in subsequent experiments which demonstratedÂ that the 29 nucleotide deletion decreases viral replication in a number of different cell types. In other words, this virus has reduced fitness compared with a virus containing a full Orf8.