DNA is transcripted into RNA which is translated into proteins, which are the main structural components of life.
MicroRNA binds to the RNA transcripts, preventing them from being translated into proteins. The article title is misleading because we usually consider DNA to be our genes, and MicroRNA affects gene expression rather than genes themselves.
RNA interference, including interference by MicroRNA was discovered decades ago but no one has studied interference by foreign RNA in food. It's mostly been studied in the context of viruses or transgenic cells.