The current virus causing all the problems belongs to the human coronavirus family. The scientific literature has cataloged, named, a little more than 40 in this virus family. The majority of them are zoonotic. That term means they started in animals and somehow were transmitted to people. An example of that is a viral disease in cattle called contagious bovine pleuropneumonia. It was a deadly disease in cattle in the 19th century, and late in that century, cattle herds were heavily culled to eliminate the disease. It was probably in that time period that it jumped from cattle to humans and is one of the viruses that cause the common cold.
There is another family of viruses called Retroviruses. After I read about them, I wondered if they were not the first family of viruses to appear because they appear to be more primitive and only have RNA. To infect a cell, the RNA must be converted to DNA. That process is called reverse transcription. It is not a very accurate method of producing DNA so that the second generation can be quite different from the first one. An example of that is HIV, and the changes in the DNA make it very hard to treat.
Viruses and Retroviruses hijack the cell’s machinery to make copies of themselves. They are in the DNA of that cell. It seemed to me they could be passed on from parent to child. I could not figure out why. I then ran across this sentence, “Our genome is littered with the remnants of viruses.” I guess they are there, but no longer are able to function for some unknown reason.
If you want to know more, some good search terms are “family of viruses” and “Retroviruses.”
