Six Sigma

Biological Parallel

DNA replication achieves better than Six Sigma quality: 3.4 defects per million becomes 1 defect per 10 billion nucleotides—six orders of magnitude more precise. This isn't luck but layered quality systems: polymerase proofreading (99.9% accuracy), mismatch repair (99.999%), and excision repair (99.99999%). The heart beats 3 billion times per lifetime with near-zero defects because sinoatrial cells, Purkinje fibers, and feedback mechanisms create redundant quality gates. Six Sigma formalizes biology's multi-layer verification: critical processes require cascading error-prevention systems, not single checkpoints.