COVID-19: emergence and mutational diversification of SARS-CoV-2.

The origin of the SARS-CoV-2 virus is not yet defined, but a viral zoonosis from bats - with or without an alternative animal as an intermediate host - is still the most likely hypothesis. The intensive virological and epidemiological research combined with massive sequencing efforts of whole viral genomes allowed an unprecedented analysis of an unfolding pandemic at the level of viral evolution with the documentation of extinction events, prevalence increases and rise to dominance for different viral lineages that provide not only fundamental insights into mechanisms of viral evolution, but influence also public health measures to contain the virus.