‘Gene within a gene’ found in SARS-CoV-2 – LiveScience excerpt

Researchers have uncovered a mysterious gene in the genetic code of the coronavirus SARS-CoV-2 – a segment virtually hidden from view in the virus’s genome, and largely overlooked until now.

The newly identified gene – called ORF3d – is an example of what’s called an overlapping gene: a kind of ‘gene within a gene’ that’s effectively concealed in a string of nucleotides, because of the way it overlaps the coded sequences of other genes.

“In terms of genome size, SARS-CoV-2 and its relatives are among the longest RNA viruses that exist,” explains bioinformatician Chase Nelson from the American Museum of Natural History.

“They are thus perhaps more prone to ‘genomic trickery’ than other RNA viruses.”

Viruses are actually quite prone to hosting overlapping genes, so it’s not exactly a shocking discovery. Whether ORF3d truly represents genomic trickery remains to be seen, but in any case, it’s certainly tricky to see.

Overlapping genes are difficult to identify in genetic sequences, as genomic scan systems can often miss them when running through strings of genetic code: programmed to pick up individual genes, but not necessarily seeing overarching instructions shared between the nucleotides of adjacent genes in a sequence.

In the context of viruses like SARS-CoV-2, that could make for a serious blind spot. Scientists have been racing to understand as much as possible about this devastating virus since early this year, and while some aspects of its genetic make-up have been elucidated (including the firm consensus that it was not ‘made in a lab’), much remains that we just don’t know yet.

“Missing overlapping genes puts us in peril of overlooking important aspects of viral biology,” Nelson says.

“Overlapping genes may be one of an arsenal of ways in which coronaviruses have evolved to replicate efficiently, thwart host immunity, or get themselves transmitted.”

As for ORF3d, there’s much yet to learn about why… 

To learn more about this discovery, please CLICK HERE.

Original article written by Peter Dockrill.