Mixing and matching of genes is called recombination.

11-20-2008    Usually only one kind of virus infects a cell at any one time. Sometimes, though, two different kinds of virus can infect the same cell. This can sometimes result in a new virus made up of parts of the other two. But this only happens in very special cases.

  One such example was the Spanish flu. This disease spread worldwide right after World War I and killed upwards of 25 million people. The virus that caused the Spanish flu didn't exist before 1918. Experts think that it was a mix of human and bird flu viruses.

  Most likely someone was infected by both a bird and a human flu virus. The bird flu probably picked up some parts from the human virus that made it easier to spread and harder for the body to fight off.  But this kind of thing can't happen with the cold virus and Ebola. To be able to do this kind of mixing and matching, the viruses need to have very similar genetic material. And the cold virus and Ebola do not.

  Mixing and matching of genes is called recombination.  It can only happen between two pieces of DNA or RNA that have sections that are very similar. This is so the two pieces of genetic material can line up with each other and swap at these points….

The instructions for making new viruses are contained in a virus' genes. Each kind of virus has a different set of genes arranged in a different way.  What this means is that when two very different viruses recombine, the new virus will have a jumble of genes. Some genes needed to hijack a cell might go missing. Or those needed to make the outside of the virus might go missing.

  Or there might be duplicates of genes so that a mix of two shell proteins gets made. Or any number of other possibilities. The end result will almost certainly be something that can't do much of anything. And certainly not be a killer cold/Ebola virus!  While this is pretty much impossible in nature, it might be possible in a lab….

  In the past few years scientists have been able to create life (sort of). For example, at the beginning of 2008 scientists made a bacteria's DNA from scratch. Then they stuck it into a bacterium. The bacterium now used this new DNA as its instruction manual. Voila, life.

  Scientists have also created viruses from scratch. Because they are so simple, this is even easier than making a bacterium.

  Scientists had to stitch together 580,000 DNA letters in the right order to make a bacteria.  An Ebola virus only takes 19,000. And a cold virus 7,200!

  So scientists can pretty easily make an Ebola virus or a cold virus in the lab. But combining them into a supervirus is a whole different story.  By

Julia Oh, Stanford University     https://genetics.thetech.org/ask/ask290