Complex sentence: Arctic apples are a suite of trademarked apples that contain a nonbrowning trait derived by gene silencing to suppress the expression of PPO, thus preventing the fruit from browning.
Split into simpler sentences: Arctic Apples are a suite of trademarked apples that contain a nonbrowning trait. Specifically, gene silencing is used to turn down the expression of polyphenol oxidase (PPO), thus preventing the fruit from browning.