Figure 4.

A simple auto-regulatory device represented using SBOL versions 1, 2, and 3. In the SBOL1 example, the structure of the unit is captured, but the regulatory function is not. In the SBOL2 example, the structure is captured using a ComponentDefinition, the function is captured in a separate ModuleDefinition, and the two objects are connected using MapsTo relations. In the SBOL3 example, both the structure and function are captured by a single Component, under which the SubComponent and Interaction objects can co-exist. Diagrams are drawn using SBOL Visual notation (Beal et al., 2019).