Poliovirus was an excellent model to prove that viruses can be synthesized from scratch; however, the techniques that Dr. Wimmer and his colleagues used to synthesize poliovirus were deliberately crude. New techniques for synthesizing DNA have continued to become more sophisticated over time and whole custom viral genomes can now be ordered over the internet from several companies. Many companies routinely screen their orders to ensure that they are not supplying genomes for select agents and that they are going to reputable institutes, but are not required to do so by law.
One notable technical improvement using programmable microchips accelerates the rate at which genes and genomes can be synthesized by a hundred-fold or more. Where it took Dr. Wimmer and his colleagues three years to synthesize the 7,500 nucleotides of poliovirus, a team led by Dr. George Church at Harvard Medical School and Dr. Xiaolian Gao of the University of Houston employing programmable DNA microchips took only months to synthesize a DNA molecule of 14,500 nucleotides in length. This same team is now at work synthesizing a 777,000 nucleotide genome of a Mycoplasma bacterium. By comparison, the smallpox virus contains only about 186,000 nucleotides.