It is known that bacteria over time form a resistance to antibiotics and environmental factors. The same applies to viruses. This feature is caused by the evolution of microorganisms and the desire to survive in the process though not natural, but selection.
Scientists from the joint genome Institute found that during the formation of resistance in bacteria is changing the genetic code embedded in their DNA. Data were established during laboratory studies. While scientists can't exactly answer, how does this mechanism, but work in this direction are underway.
The study of bacteria will help you to understand genetic diseases of man and other serious pathology of our body.