Sunday, March 8, 2020

A lesson on virus, COVID-19 a.k.a Coronavirus

COVID-19 - Coronavirus
In the field of genetics I study 'transposable elements', which are tiny fragments of inactive, viral DNA that were historically inserted into and survive in the genes of cells of living organisms. It's thought that human DNA developed, in part as a result of around 8% inserted viral DNA that became fragmented and interspersed among other protein coding or regulatory DNA. Further, the function of the vast majority of our DNA is unknown, we know its there, but we don't know exactly what it is there for.

A virus like Corona is a functioning arrangement of proteins that protect not its DNA but the product of DNA, its RNA. This unique arrangement of proteins ensures the RNA's survival as code to make the proteins that protect it. The virus, its protective protein and DNA or RNA will die if exposed. So, survival is dependent on hitching a ride in an organism and freeloading in a cell where, once inserted, the virus DNA or RNA may attract that cells DNA/RNA-replication-proteins.

If the inserted sequences are attractive, they will dominate the activity of that cells replication-proteins. After being replicated many-many times over, the co-opted cell will produce the virus protein and assemble it into more viruses that will eventually kill the cell and move on to other cells where the process will repeat. The protein arrangement of a replicating virus, binds to a cell membrane before injecting its DNA or RNA into that cell. Ultimately the activity may invite immune system cells to identify, fight and kill infected cells before the virus can replicate further.

In some viral genes DNA that has become separate 'transposable elements' or fragments can lie dormant in cell genes for very long periods and their positions in the gene can change. Sometimes long sequences of a genes DNA break, when this occurs viral fragments located near proteins, attracted to recombine the break may also be assembled with other DNA that make the viral fragment more or less attractive to DNA-replication-proteins.

COVID-19 is a much more simple-recent addition. It injects not DNA, but the post DNA replication product known as RNA. This occurs after the proteins of COVID-19 connect to a human cell at least via receptor known as ACE2. If you are healthy and your immune system finely tuned, in more than 99% of cases the infected cell will be killed and virus dismantled.

COVID-19 RNA Replication and Protein Assembly
The most recent data suggests every infected person is successfully passing COVID-19 to 2.5 other people, many of whom do not express symptoms. It is quite likely COVID-19 will tail off with the rising temperatures in the northern hemisphere. In 2003 other Coronaviruses, SARS peaked in March and April and was done by May. MERS appeared in 2012, peaked in spring of 2014, and hasn't spread since then. Although Corona may already be more widespread, it is likely the panic presently being experienced around the world will subside and not re-arise in the winter of 2020/21. Since RNA viruses are less resilient that DNA viruses, I predict, Corona will disappear from our radar screens and like most "fake news" we will look back, scratch our heads and deeply consider how we should assess future events like this one.

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