Question

1. Coronaviruses are known to have higher than usual recombination frequencies for RNA viruses. How does recombination play a role in genomic variation? How might it affect the pathology and spread of SARS-CoV-2? anything helps

Answer 1

1. Recombination is a process by which genetic diversity are generated by the crossing over of two nucleotide strands and occurs when at least two viral genomes infect the same host cell. In viruses, self recombination occurs when two viral genomes recombine by homologous crossing over resulting in switching information. Recombination by independent assortment or reasortment takes place in the viruses with segmented genomes. In this case, genes that reside on different pieces of nucleic acid are randomly assorted. As a result, genomic variation can occur and viruses with new antigenic determinanats develope.

                                                                                              

                                                                  

                                                                                                                                         

                                                          

                                                                             

                                                                    

                                                                    

2. SARS-CoV-2 is a RNA virus so it is more prone to mutations which leads to genomic variation. In case of RNA viruses the rate of mutation is 10-6 and 10-4 substitution per nucleotide site per cell infection (s/n/c). These mutations could result in changes in viral virulence, infectivity and transmissibiliity. SARS-CoV-2 has very less similarity with the previously appeared coronaviruses such as MERS-CoV and SARS-CoV, therefore it is named as a novel CoV. It is reported that spike glycoprotein of SARS-CoV-2 is modified via homologous recombination. The variations in the spike protein gene as well as other genetic variation enables its identification and further treatment. To check its spread and to combat this novel infection, researchers need to understand its pathogenecity and mutations. Drugs or therapies designed by targeting a specific protein or gene would not show any effect on the disease or the virus due to these genetic variation.