Maize Kernel Variegation: 2D Transposon Lineage Map

Ac/Ds Transposon System

Excision rate per division 8%

Cell divisions simulated 7 (128 cells)

Growth speed 1.0×

Kernel Readout

Pigmented (purple)

Revertant sectors

Avg. sector size

0 cells

Developmental gen.

0 / 0

How it works

In Barbara McClintock's maize, the Ds (Dissociation) element sits inside the C1 pigment gene, knocking it out and leaving the kernel colorless. Ds cannot move on its own — it needs the enzyme made by a second element, Ac (Activator), elsewhere in the genome. When Ac is present, Ds can excise from C1 at any mitotic division, restoring the gene in that cell and every descendant of it, painting a purple sector.

Cell divides -> Ds excises with prob. p (only if Ac present)
Once excised -> gene restored -> ALL daughter cells inherit purple
P(cell still colorless after G divisions) = (1 - p)^G
Earlier excision -> more divisions left -> LARGER sector
Later excision  -> fewer divisions left -> SMALLER sector, more spots

This 2D simulator grows the same stochastic lineage tree as the 3D model: starting from one founder cell, each division splits the tissue in a unit (u,v) map — alternating axis, like real anticlinal/periclinal cell walls — and at every division each still-colorless lineage independently rolls the excision probability. Three linked views show the identical underlying data: a polar cross-section of the kernel (u = angle around the cob, v = radial depth from tip to base), the raw unwrapped (u,v) map, and a generation ladder showing every division level stacked top-to-bottom. Big blocks of color come from early jumps; fine speckling comes from late ones — exactly the variegated pattern that led McClintock to propose mobile genetic elements in 1950, work that won her the 1983 Nobel Prize.

+Ac / −Ac — toggles whether the transposase needed to mobilize Ds exists at all; with Ac silent, excision rate is forced to zero (the classic no-Ac control: a fully colorless kernel).
Excision rate — per-division probability p that Ds jumps out in a given colorless lineage.
Cell divisions — depth of the lineage tree (2^G final cells).
Drag the cross-section — rotate the kernel view around its axis.
Grow New Kernel — re-runs the stochastic lineage tree with a fresh random seed and replays the growth animation across all three panels.

Colorless (Ds intact, C1 off) Purple (Ds excised, C1 on)

drag to rotate

Unwrapped lineage map (u × v)

Generation ladder