What if we want to use a Risk Group 3 or 4 organism?

Don't do it. Find a substitute.

Risk Groups 3 and 4 include the most serious and deadly pathogens in the world. They require extremely stringent safety precautions and specialized lab facilities. There is no compelling reason for any iGEM team to choose to work with Risk Group 3 or 4 organisms, when instead you could choose from the vast array of interesting project topics that use only Risk Group 1 or 2 organisms.

Using safer substitutes for dangerous organisms is entirely appropriate for iGEM. For example, the 2013 Paris Bettencourt team studied tuberculosis. Mycobacterium tuberculosis is a Risk Group 3 organism, so for safety reasons, they substituted a related Risk Group 2 organism (Mycobacterium smegmatis) in their experiments. These experiments were a proof of principle for their project ideas.

Animals and plants have no Risk Group

The four Risk Groups only apply to microorganisms (bacteria, fungi, and viruses). For animals, plants, and other multicellular organisms, there are different safety guidelines. Please consult with your advisor or university authorities if you plan to do experiments with animals and plants.

If you are using a part from an animal or plant, you should consider the function of the part, and consider whether it might be dangerous to humans. For example, the gene for Green Fluorescent Protein (GFP) comes from the jellyfish Aequorea victoria, which does not have a Risk Group. GFP is only a fluorescent protein, absorbing and emitting light, so it is safe for humans and you can use it in a Safety Level 1 lab. But if you consider a different gene from A. victoria, such as the gene for the toxin in its stinging tentacles, you might conclude that you should only use that gene under strict safety conditions!