The Mustard Plant Principle

Same genes, different regulation. Buds don't have their own gene program — they reuse the trunk's program with modifier genes that change depth, scale, and angle. A small regulatory change produces a dramatically different organism, just like wild mustard → broccoli, cabbage, kohlrabi, kale.

"If they selected for lateral buds, they got Brussels sprouts. If they selected for terminal buds, they got cabbage. If they selected for flower clusters, they got cauliflower. If they selected for leaves, they got kale... just time and manner and place — without really changing the basic anatomy of the plant."
— Marc Kirschner, Harvard lecture on Evolvability
Trunk (shared program) Buds (same program, modified)

The Mustard Plant Principle: In v1-v3, buds had 9 independent genes — a separate developmental program. Here, buds share the trunk's 9 genes and are modified by just 5 regulatory genes: depthMod (how deep the bud grows), scaleMod (how large), angleMod (rotational offset), flipMod (mirror the program), and suppressGene (silence one trunk gene in the bud). Total: 16 genes (vs 20+ in earlier prototypes). Fewer genes, but stronger facilitated variation — mutate the trunk, and buds change with it because they're derived from the same program.