CDC/NIH exempts research with DNA molecules that:

1. Are not in organisms or viruses;
    
2. Consist entirely of DNA segments from a single nonchromosomal or viral DNA source, though one or more of the segments may be a synthetic equivalent;
    
3. Consist entirely of DNA from a prokaryotic host including its indigenous plasmids or viruses when propagated only in that host (or closely related strain of the same species), or when transferred to another host by well established physiological means;
    
4. Consist entirely of DNA from a eukaryotic host including its chloroplasts, mitochondria, or plasmids (but excluding viruses) when propogated only in that host (or closely related strain of the same species);
    
5. Consist entirely of DNA segments from different species that exchange DNA by known physiological processes, though one or more of the segments may be a synthetic equivalent. See Appendices A-1 through A-IV* (see pages 28-29 ) for the list of exchangers that are exempt from NIH Guidelines;
    
6. Do not present a significant risk to health or the environment. See Appendix C, Exemptions under Section III-F-6 *(see pages 35-38) for exemptions.