How are recombinant and synthetic nucleic acids defined under the amended NIH Guidelines?
In the amended NIH Guidelines, recombinant and synthetic nucleic acid molecules are defined as:
- Molecules that (a) are constructed by joining nucleic acid molecules and (b) can replicate in a living cell (i.e. recombinant nucleic acids);
- Nucleic acid molecules that are chemically or by other means synthesized or amplified, including those that are chemically or otherwise modified but can base pair with naturally occurring nucleic acid molecules (i.e. synthetic nucleic acids); or
- Molecules that result from the replication of those described in (i) or (ii) above.
What has changed with respect to the scope of the NIH Guidelines?
The scope of the NIH Guidelines has been expanded to include synthetic as well as recombinant nucleic acid molecules. As with recombinant nucleic acids, certain classes of basic and clinical research with synthetic nucleic acids will be exempt. As specifically stated in Section I-A of the NIH Guidelines, the purpose is to “specify practices for constructing and handling: (1) recombinant nucleic acid molecules; (2) synthetic nucleic acid molecules, including those that are chemically or otherwise modified but can base pair with naturally occurring nucleic acid molecules; and (3) cells, organisms, and viruses containing such molecules.”
When do the requirements under the amended NIH Guidelines go into effect?
The changes are effective March 5, 2013. All ongoing and proposed experiments with synthetic nucleic acids that are newly subject to the amended NIH Guidelines need to be registered by the Principal Investigator with the IBC by this date.
What basic research with synthetic nucleic acids is exempt from the amended NIH Guidelines?
Exemption of research with synthetic nucleic acids from the NIH Guidelines follows the same rules as research with recombinant nucleic acids. Specifically, research with synthetic or recombinant nucleic acids is exempt from the NIH Guidelines if:
- Their introduction into a biological system is not expected to present a biosafety risk that requires review by an IBC;
- The introduction of these nucleic acid molecules into biological systems would be akin to processes of nucleic acid transfer that already occurs in nature and does not change the biosafety practices used for the natural organism;
- It is not contained in cells, organisms, or viruses;
- The recombinant or synthetic nucleic acids can neither replicate nor generate nucleic acids capable of replicating in any living cell;
- The synthetic or recombinant nucleic acids are not designed to integrate into DNA; or
- The synthetic or recombinant nucleic acids do not produce a toxin that is lethal to vertebrates with an LD50 lower than 100ng per kilogram of bodyweight.
Is the chemical synthesis of nucleic acids subject to the NIH Guidelines?
No. The amended NIH Guidelines do not cover the chemical synthesis of nucleic acids. While the scope of the amended NIH Guidelines refers to “constructing” nucleic acids, the amended NIH Guidelines exempts research with nucleic acids that are not contained in cells, organisms, or viruses. Therefore, the chemical synthesis of nucleic acids is exempt. The amended NIH Guidelines only apply once synthetic nucleic acids are placed in a biological system.
Does the synthesis of a naturally occurring organism fall under the amended NIH Guidelines?
The NIH Guidelines exempts research with recombinant or synthetic nucleic acid molecules that consist entirely of DNA sequences that exist contemporaneously in nature. This exemption is modified from the previous exemption and now only applies to those molecules that consist solely of the exact recombinant or synthetic nucleic acid sequence from a single source that exists outside of a laboratory setting.
What clinical research with synthetic nucleic acids is covered under the amended NIH Guidelines?
Section III-C-1 of the amended NIH Guidelines covers human gene transfer experiments, i.e., research that involves the deliberate transfer into human research participants of recombinant or synthetic nucleic acid molecules, or DNA or RNA derived from recombinant or synthetic nucleic acid molecules, that meet any one of the following criteria: (1) contains more than 100 nucleotides; or (2) possesses biological properties that enable integration into the genome; or (3) have the potential to replicate in a cell; or (4) can be translated or transcribed. In contrast, synthetic oligonucleotides, such as short interfering RNAs or micro-RNAs, that are directly administered or delivered in chemical vehicles, such as nanoparticles, are very small molecules and do not share these characteristics and are exempt from the NIH Guidelines.
How does a risk assessment for research with synthetic nucleic acid molecules differ from a risk assessment for research with recombinant nucleic acid molecules?
The risk assessment framework of the NIH Guidelines uses the risk group of the parent organism as a starting point for determining the necessary containment level for the recombinant organism. The containment level might be raised or lowered depending on the specific construct and the experimental manipulations. In most instances, this risk assessment framework can be effectively applied to assess the biosafety risks of experiments with synthetic nucleic acids. However, synthetic biology research has the potential to create complex, novel organisms for which identification of a parent organism may be more difficult or may not be as relevant to the risk assessment as it is with traditional recombinant organisms.
The risk assessment may also be complicated by the limitations in predicting gene function from sequence(s) or the synergistic effects from combining sequences from different sources in a novel context. The initial assumption should be that all sequences would function as they did in the context of the original source. In such cases, the risk assessment should include at least two levels of analysis, including a consideration of the Risk Groups of the source(s) of the sequences and an assessment of the functions that may be encoded by these sequences. Other factors to consider include the percentage of the genome contributed by each parent agent, the predicted function or intended purpose of each contributing sequence, and the potential for synergistic functions that may arise with combining sequences in a novel context.
Where can I get more information about the NIH Guidelines?
Further information is available on the NIH OBA website.
If you have specific questions about the NIH Guidelines, please contact the NIH Office of Biotechnology Activities by
Office of Biotechnology Activities
National Institutes of Health
6705 Rockledge Drive
20892-7985 (20817 for non-USPS mail).