Before revision:  Evolutionary relationship analysis shows that about 13 strains of the COVID-19 virus sequenced in 5 countriesare very likely to be connected to or can potentially lead researchers to find the first generation COVID-19 virus and its origin .
After revision:  Evolutionary relationship analysis shows that about 13 strains of the COVID-19 strains isolated from human hosts has steadily increased from December 2019 to March 2020, suggesting COVID-19 virus and its origin .