Junctions, a term in telecommunications, are devices installed between cables, featuring certain insulation and sealing properties to enable the continuous operation of two or more cables. In genetic engineering, they refer to sequences that allow two DNA molecules or the ends of a single DNA molecule to be paired and covalently linked by enzymes. Currently, artificial hexamer junctions (containing a specific enzyme's cutting site) are commonly used, and multiple hexamer junctions can be connected to form poly junctions (polyl).inker)。