page_title: Hazards of synthetic biology
section_title: Intrinsic
hierarchical_section_title: Hazards of synthetic biology / Hazard controls / Intrinsic
caption_attribution_description: English: Colonies that are Arginine Auxotrophs are depicted as only being able to grow on media where Arginine is present. Same colonies represented as Prototrophs (being able to grow with minimal media and producing all necessary from the media metabolites)
context_page_description: The hazards of synthetic biology include biosafety hazards to workers and the public, biosecurity hazards stemming from deliberate engineering of organisms to cause harm, and hazards to the environment. The biosafety hazards are similar to those for existing fields of biotechnology, mainly exposure to pathogens and toxic chemicals; however, novel synthetic organisms may have novel risks. For biosecurity, there is concern that synthetic or redesigned organisms could theoretically be used for bioterrorism. Potential biosecurity risks include recreating known pathogens from scratch, engineering existing pathogens to be more dangerous, and engineering microbes to produce harmful biochemicals. Lastly, environmental hazards include adverse effects on biodiversity and ecosystem services, including potential changes to land use resulting from agricultural use of synthetic organisms.
  In general, existing hazard controls, risk assessment methodologies, and regulations developed for traditional genetically modified organisms also apply to synthetic organisms.
context_section_description: Intrinsic biocontainment is the proactive design of functionalities or deficiencies into organisms and systems to reduce their hazards.  It is unique to engineered organisms such as GMOs and synthetic organisms, and is an example of hazard substitution and of prevention through design.  Intrinsic biocontainment can have many goals, including controlling growth in the laboratory or after an unintentional release, preventing horizontal gene transfer to natural cells, preventing use for bioterrorism, or protecting the intellectual property of the organism's designers.  There has been concern that existing genetic safeguards are not reliable enough due to the organism's ability to lose them through mutation.  However, they may be useful in combination with other hazard controls, and may provide enhanced protections relative to GMOs.
  Many approaches fall under the umbrella of intrinsic biocontainment.  Auxotrophy is the inability of an organism to synthesize a particular compound required for its growth, meaning that the organism cannot survive unless the compound is provided to it.  A kill switch is a pathway that initiates cell death that is triggered by a signal from humans.  Inability of the organisms to replicate is another such method.
  Methods specific to plants include cytoplasmic male sterility, where viable pollen cannot be produced; and transplastomic plants where modifications are made only to the chloroplast DNA, which is not incorporated into pollen.
  Methods specific to viral vectors include splitting key components between multiple plasmids, omitting accessory proteins related to the wild-type virus' function as a pathogen but not as a vector, and the use of self-inactivating vectors.
  It has been speculated that xenobiology, the use of alternative biochemistry that differs from natural DNA and proteins, may enable novel intrinsic biocontainment methods that are not possible with traditional GMOs.  This would involve engineering organisms that use artificial xeno nucleic acids (XNA) instead of DNA and RNA, or that have an altered or expanded genetic code.  These would be theoretically incapable of horizontal gene transfer to natural cells.  There is speculation that these methods may have lower failure rates than traditional methods.
caption: Auxotrophy is an intrinsic biocontainment method where an organism is unable to synthesize a particular compound required for its growth.  This is intended to reduce the risk that it can survive after an accidental release or exposure event.
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