Specific Virus Examples: 
  
 Synthetic Polio Virus - July 12 ,2002 : Molecular Origin of Life Research or Bioterrorism?  

  Wimmer and his team then mixed the lab-made DNA with an enzyme that converts DNA into RNA.
Next, they added the resulting strands to a mixture of chemicals similar to that in the cells that poliovirus typically invades. This brew generated whole polioviruses that subsequent tests in cells and animals confirmed as infectious.
   To distinguish any synthesized viruses from lab contaminants, the investigators introduced subtle changes into the virus' genetic code that didn't alter the proteins it encodes. Unexpectedly, however, the newly created viruses turned out to be much less potent than the typical lab strain. Higher doses of the synthetic poliovirus were needed to kill mice, for example.  

     In 1978 Phi X, a virus that infects bacteria but is harmless to humans, was the first virus ever sequenced. By 2004 Craig Venter's (of Genomic sequencing fame) and his research group (including longtime collaborators Nobel Laureate Hamilton O. Smith of the Institute for Biological Energy Alternatives (IBEA), and Clyde A. Hutchinson of the University of North Carolina, Chapel Hill) at  in Rockville, Maryland , in just 14 days, created an artificial version of Phi X-174 by piecing together synthetic DNA ordered from a biotechnology company. They used a technique called polymerase cycle assembly (PCA) to link the strands of DNA together. 
     The sequence and assembly of the synthetic genome matches up nearly perfectly with the sequenced genome of the natural virus. Each strand of DNA neatly overlaps its neighboring strands by 20 letters of genetic code. The new virus also infects bacterial cells just like the natural virus does.
     The goal of the IBEA research is to create a synthetic genome that would be 100 to 1,000 times larger than the phi X virus. Someday, researchers hope to engineer fleets of self-replicating microbes that do everything from scrubbing down emissions at coal plants to producing enough hydrogen to power cars and trucks run by hydrogen-fuel cells rather than gasoline.
  

    October 2005      The 1918 Spanish Flu Virus is Reconstructed
                                                                                 http://www.cdc.gov/od/oc/media/pressrel/r051005.htm
          Jeffery K. Taubenberger, a molecular pathologist at the Armed Forces Institute of Pathology in Rockville, MD at a CDC Bio-Safety-Level 3 CDC lab reconstructed the genome of the 1918 lethal virus as reported in the October 7, 2005 issue of Science. They successfully reconstructed  the influenza A (H1N1) virus responsible for the 1918 “Spanish flu” pandemic (pic + pic). The influenza pandemic of 1918-19 killed an estimated 20 to 50 million people worldwide, many more than the subsequent pandemics of the 20th century. The Spanish flu virus of the 1918 pandemic was probably a strain that originated in birds. Scientists have found the 1918 virus shares genetic mutations with the bird flu virus now circulating in Asia.
      Taubenberger and his colleagues were able to piece together the virus's genes from two unusual sources. One source was fingernail-size pieces of lung tissue removed at autopsy from  a 21-year-old soldier who died in 1918 at Fort Jackson in South Carolina. He was among the pandemic's 675,000 American victims and he provided intact pieces of viral RNA that could be analysed and sequenced.. The other source was the frozen body of an Inuit woman who died of influenza in November 1918 and was buried in the permafrost.
         The virus's eight "RNA gene segments" were in pieces. Using gene sequencing and the polymerase chain reaction they reassembled the virus. Two of the 8 genes are considered to be of greatest importance for the virulence of the virus: the genes for hemagglutinin (HA) and neuraminidase (NA).  Hemagglutinin type 5 [H5] and Neuraminidase type 1 [N1] are protein surface coatings of the virus. Hemagglutinin A is a glycoprotein that binds the virus to the host cell. There are at least 16 different HA antigens. Neuraminidase is an antigenic glycoprotein enzyme found on the surface of the flu virus. Nine neuraminidase subtypes are known, many occurring only in various species of ducks and chickens. Subtypes N1 and N2 have been positively linked to epidemics in man. The neuraminidases aid in the efficiency of virus release from  infected cells.
  
  

 A bacterial example of Synthetic Biology 
   
J. Craig Venter, a principle investigator (P.I.) of the Human Genome Project is attempting
      to make a synthetic new type of bacterium using DNA manufactured in the lab; using the    sequenced the genes of a bacterium called Mycoplasma genitalium, a gram-positive parasitic bacterium, whose primary infection site may be the human urogenital tract. It probably causes non-gonococcal urethritis.  The complete nucleotide sequence is 580,073 base pairs, the smallest known genome of any free-living organism, has been determined. A total of only 517 genes (480 encoding for proteins; the rest for RNAs) were identified that included genes required for DNA replication, transcription and translation, DNA repair, cellular transport, and energy metabolism.
  
    > researchers began systematically removing genes to determine how many genes
           are essential for life.  In 1999, they published the narrowed the needs of M. genitalium
           to between 265 & 350 genes.
    > How many genes does it take to make an organism? What is the minimum genes a cell needs?
         The scientists at The Institute for Genomic Research (TIGR) who determined the Mycoplasma
         genitalium sequence followed this work by systematically destroying its genes (by mutating them
         with insertions) to see which ones are essential to life and which are dispensable. Of the 480
         protein-encoding genes, they conclude that only 265–350 of them are essential to life.
    > The next step is to artificially assemble these 300+ genes to create a synthetic cell.