The genome variants of SARS-COV-2 strain from Bangladesh
The first complete genome sequence of SARS-CoV-2 (CHRF_nCoV19_0001)
from a Bangladeshi isolate was submitted to the GISAID database on 12
May 2020. Bangladesh based Child Health Research Foundation conducted
the sequencing project [38]. As of July 17, genome sequencing of 222
samples from Bangladeshi SARS-CoV-2 isolates was submitted on the GISAID
database, of which 173 samples were sequenced by the Bangladesh Council
of Scientific and Industrial Research (BCSIR) [39]. Jashore
University of Science and Technology had announced on 24 June 2020 that
they had sequenced the complete genome of another three SARS-CoV-2
strain that is responsible for the respiratory infections in the
southern part of the country [40]. A comparative study of the
Bangladeshi strain and other strains around the world revealed that
there were 9 single-nucleotide variants in the Bangladeshi strain,
mostly in the ORF1ab gene and also a sequence containing 3 successive
variants in the N protein which probably reflects a weaker strain of
SARS-CoV-2 and explain the reason of low mortality rate in Bangladesh
[41]. Phylogenetic analysis elucidated that there is sequence
homology among the Bangladeshi strains and strains from Taiwan, Greece
and Kazakhstan which implicates that the virus strains found in these
countries were descendent from a weaker strain of the same origin,
probably Michigan or Arizona in the United States [41]. Another
investigation of 184 genome samples of SARS-CoV-2 across the country
found 634 mutations located in the whole genome that results in 274
nonsynonymous substitutions in 22 different proteins. Among the spike
protein variants circulating across the country, G614 is most prevalent
followed by L323 (94%) in RNA- dependent RNA polymerase (RdRp), K203
(82%) and R204 (82%) in nucleocapsid, and F120 (78%) in NSP2. These
mutations implicated a close homology with a European haplotype of
SARS-CoV-2. These sequencing data will help to predict prognosis and
develop an effective vaccine for the treatment of COVID-19 patients in
Bangladesh.