Comparative genomics and diversity of SARS-CoV-2 suggest potential regional virulence

It is widely known fact about the global pandemic caused by Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) to humans, which imposed immediate lockdown of effected territories in the prevailing provinces. However, few provinces were able to control infection severity with lower death rates. Interestingly three types of genomic features were noticed through comparative genomics in the available genome sequences SARS-CoV-2, due to the insertion/deletions of orf3a, orf6, orf7a and orf7b. Whole genome phylogeny (n=75 genomes) revealed a large diversity within the SARS-CoV-2, and distributed in 6 clusters namely China, Diamond princess, Asian, European, USA and Beijing. This study asserts diversity in the genome with high mutation rate and migration of carriers over the world. Here, we describe the polymorphic loci of Spike glycoprotein and its putative mechanism for pathogenicity, which unveiled the presence of GPI anchor amidation, PPI hotspot, O-linked glycosylation, catalytic site, Iron binding site, signal cleavage, disulphide linkage, sulfation, transmembrane region, and C-terminal signal sites. Mutational changes at spike glycoprotein of South Korea, India, Greece, Spain, Australia, Sweden and Yunnan samples possibly suggest the prevalence of mutated strains with either low or high virulence. The regions at the spike glycoprotein also have high binding capacity to angiotensin converting enzyme 2 (ACE2) suggesting a key link for explaining damage to multiple organs including lungs, kidney and heart. Factors influencing the mutations at the spike glycoprotein region will need to be investigated to understand and neutralize the upsurge of the alarming Pandemic and to control the global spread of the disease.