Determining the variations in SARS-CoV-2 variant is considered main factor for understanding the pathogenic mechanisms, aid in diagnosis, prevention and treatment. The present study aimed to determine the genetic variations of SARS-CoV-2. The sequences of SARS-CoV-2 were ob-tained from National Center for Biotechnology Information (NCBI) and studied according to the time of isolation and their origin. The genome sequence of SARS-CoV-2 accession number NC_045512 which represented the first isolated sequence of SARS-CoV-2 (Wuhan strain) was used as the reference sequence. The obtained genome sequences of SARS-CoV-2 were aligned against this Wu-han strain and variations among nucleotides and proteins were examined. The sequence of SARS-CoV-2 accession number MT577016 showed very low homology 98.75 % compared to Wuhan strain NC_045512. The analysis identified 301 nucleotide changes, which correspond to 258 different mutations; most of them 80 % (207/258) were missense point mutations followed by 17.1 % (44/258) silent point mutations. The critical mutations occurred in viral structural genes; 16.7 % (43/258) mutations reported in S gene and 1 missense mutation was observed in E gene. Our finding showed the lowest homology and relatively distant phylogenetic relation of this SARS-CoV-2 variant with Wuhan strain along with high frequency of mutations including those in spike S and envelope E genes.
Keywords: COVID-19, genetic variation, homology, phy-logenetic, SARS-CoV-2
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