Sensi Seed Co. is where the written history of cannabis genetics begins. Ben Dronkers founded it in Amsterdam in 1985 after a decade of traveling Asia, Africa, and the Americas collecting landraces, and the library he assembled became the largest genetic archive in the world.

Skunk #1, Northern Lights, and Jack Herer were built or preserved inside it, which means nearly every lineage chart on this site eventually touches a Sensi plant. The crosses below connect to that library.