Question

During the early days of the outbreak, international collaborations between researchers worked faster than they ever have to sequence the genome of SARS-CoV-2 so that they would have the genomic sequence of the virus. Explain why this was critical for developing the necessary PCR test for diagnosis.

Answer 1

PCR test require primers. A primer is a short single-stranded nucleic acid used in the initiation of DNA synthesis by all living organisms; DNA polymerases, the enzymes responsible for replication of DNA, are only capable of attaching nucleotides to the 3'-end of an existing nucleic acid, requiring a primer to be attached to the template before DNA polymerase can start a complementary strand.

The polymerase chain reaction uses a pair of custom primers to direct DNA elongation at opposite ends of the amplifying sequence towards each other. Usually these primers are between 18 and 24 bases in length, and will code only for the different upstream and downstream sites of the amplified chain.

And for this designing complementary sequence to the DNA template, sequencing the viral genome is vital.