Through careful examination of viral structural/non-structural proteins as well as infection mechanism, the 2003 SARS-CoV and the current 2019nCoV are thought to be very similar in phylogenic. Based on complete sequencing, the current 2019-nCoV is evolutionary related to SARS-CoV long range-conserved amino acid sequences with a few variations in the accessory proteins and base substitutions in non-structural proteins (Wu et al., 2020). Even before 2003, many different coronaviruses have similar conserved proteins and replication pathway all leading to annually 15-30% of respiratory infections in humans. Individuals of older age, with pre-existing illnesses, or with compromised immunity are the most susceptible to infections and often associated with the highest mortality. Currently, the 2019-nCoV has been reported to have the highest pathenogenicity and fatality out of all coronaviruses. This can be explained based on differences in tolerance to genetic variability. For instance, both the 2003 SARS-CoV and current 2019-nCoV are very tolerant to genetic variations. Both strains of coronaviruses have shown their potential to pass through species barrier from bats, pangolins, mice, and bovine all the way to mammals including humans (Guan et al., 2003). In other words, higher tolerance to genetic variability could imply greater chances of horizontal gene transfer across species. Looking back to 2003, the same characteristics can be seen in SARS-CoV, where it was hypothesized to be found first in Chinese horseshoe bats in Guangdong Province.