The Sigma Xi Committee on Lectureships continues its COVID-19 series on Friday, September 25, from 2:00 p.m.–3:00 p.m. ET on Zoom. Speaker: David Deamer, PhD, Research Professor, Biomolecular Engineering at The University of California at Santa Cruz Moderator: Kirsten "Kiki" Sanford, PhD, neurophysiologist, science communicator, and host and producer of This Week in Science (TWIS) podcast Register at this link. Cost: Free Abstract: Where did the novel coronavirus come from? For that matter, where does any virus come from? The easy answer is that no one knows with certainty. However, it is clear that viruses can only reproduce in a living cell, so let's go back in time 4 billion years to the beginning of life on Earth. There are two possibilities: Perhaps there were conditions in which certain nucleic acids could assemble, then begin to grow and replicate by themselves. In that case, viruses came first and only later evolved to become infective agents. The second possibility is that cellular life originated first and incorporated a primitive version of nucleic acids capable of reproducing themselves. At some point certain species of nucleic acids escaped from a dying cell and were taken up by a living cell. Something like this still happens today when plasmids are released by bacteria and deliver genetic information to other bacteria when they incorporate the plasmids. The difference between plasmids and viral nucleic acids is that viral genomes can reproduce and make copies of themselves along with viral proteins, but plasmids cannot. A last point to make is that there are infective agents even simpler than viruses. These are called viroids, and they are little more than a ring of RNA composed of several hundred nucleotides. Viroids infect plant cells, reproduce using polymerase enzymes of the cell and can cause a variety of plant diseases. It has been suggested that viroids are remnants of the process by which cellular life originated. We will explore this possibility as an approach to understanding how viruses could have emerged and then coevolved with cellular forms of life, finally becoming infective agents like the novel coronavirus. Feel free to share this information with colleagues. Contact [hidden email] with questions. |
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