Evolutionary trajectory of SARS-CoV-2 and emerging variants

Table 1 Speculated timelines for evolutionary origins of known human coronaviruses from bats

Species	Discovery in humans	Speculated timeline of divergence for human strain	Speculated bat reservoir	References
SARS-CoV-2	2019	Human strain likely diverged from most closely related bat virus in 1969	Rhinolophus spp.	[32, 294, 295]
SARS-CoV	2003	Human strain likely diverged from bat strain in 1986	Rhinolophus spp.	[22, 53, 280, 296,297,298]
MERS-CoV	2012	Human strain likely diverged from bat strain before 1990	Taphozous perforates, Pipistrellus spp., Neoromecia spp.	[282, 299,300,301,302,303,304,305]
HCoV-OC43	1967	Human strain likely diverged from bovine strain in 1890	N/A	[276, 306]
HCoV-HKU1	2004	No supported dates of divergence have been established	N/A	[279]
HCoV-229E	1965	Human strain likely diverged from alpaca strain before 1960 and from bat strain between 1686 and 1800 CE	Hipposideros caffer ruber	[21, 56, 307]
HCoV-NL63	2004	Human strain likely diverged from bat strain between 1190 and 1449 CE	Triaenops afer	[20, 308,309,310]

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