Ethical considerations aside, if DNA-based technologies became widely used, how might they change the way evolution proceeds, as compared with the natural evolutionary mechanisms that have operated for the past 4 billion years?

Although now a days we have evidence that evolution and speciation process can happen in 1 or just a few generations (e. g. clone crayfish or the golden rain tree bug florida and there are many more) usually evolution and speciation process work at a broader scale of time. This is important because communities are evolving together and this creates equilibrium in ecosystems. If evolution happens only in several other may not adapt to these changes.

DNA technologies can be dangerous especially with bacteria because Gram Negative Bacteria have been found to be fairly capable of inter-species conjugation, this is dangerous because DNA can change bacteria in a way that may be invasive or harmful to other organism.