Developing nonbrowning Arctic apples relies upon a technique called RNA interference (RNAi).[10] This approach enables silencing of PPO expression to less than 10% of its normal expression, but does not change other aspects of the apple.[3] The RNAi process is accomplished through the use of a transgene that uses gene sequences that control PPO production.[3] Promoter and terminator gene sequences are used to support the implementation of PPO suppression genes, as is a marker gene which produces a protein (called NPTII) that makes the plant tissue resistant to the antibiotic kanamycin, allowing transformed plants to metabolize neomycin and kanamycin antibiotics.[11] This step is used to confirm that silencing PPO was successful.[3]