In the 1940's the attention of geneticists was surprisingly focused on the Escherichia coli, colon bacterium. E. coli offered many advantages such as genetically being simpler, they are easily broken open and bacterial cells have little internal structure. For the fact that the E. coli populations can double in number in twenty minutes, viruses could be grown in enormous numbers in a short period of time.
             Viruses fall into the world between living and not living. They have traits of living yet they crystallize and develop like table salt. Hershey and Chase's classic experiment showed that viral SNA entered the bacterial host cell and left the empty coat outside.
             If viral SNA goes past the host's defenses it can come across a friendly host protein (RNA polymerase). RNA polymerase can't tell between its own DNA and foreign DNA. It treats the viral DNA as if it was its own and transcribes mRNA from it, making viral mRNA. Then making new viral enzymes, later taking over the hosts' mRNA. The last act of the viral protein is to lyse (rupture) the envelope of the host cell. Lysis of E. coli cell releases hundreds of new viral particles that move to infect more host cells in a continuing cycle (the lytic cycle). There is also the lysogenic cycle that cuts into and joins the host DNA instead of destroying the host chromosomes.
             Viruses are only parasitic and can only grow in living cells. There are many types of viruses that can get to many types of cells. some use RNA others use DNA. Some start with RNA and have to change into DNA to get the virus going. There's also reverse transcriptase, which makes the DNA copy of RNA.
             Recombination is any exchange of DNA, and the first kind of recombination observed in bacteria was transfomation; which involved bacteria taking up fragments of DNA from other bacteria. Transduction is the transfer of genetic material from one bacterium to another us...