Mutant clownfish reveals how nature draws boundaries

In 1999, a clownfish (Amphiprion ocellaris) hatched in the aquarium of a tropical fish hobbyist in the UK. These clownfish are prized by aquarists for their unique pattern of three straight white bars bordered by a thin black line. But this UK fish was special: instead of the usual straight bars, it had wavy, corrugated patterns, symmetrical on both sides. The patterns were inherited across generations, leading to a lineage named "Snowflake," but the mechanism causing this irregular patterning remained a mystery.