Figure: The TC-Battle and a Conditional Exit

The TC-Battle and a Conditional Exit Two-panel diagram. Panel A shows a six-step escalating arms race between E. coli and strictly lytic T4 phage, connected by zigzag arrows and a dashed return loop. Panel B shows the conditional exit available to bacteriophage lambda: its DNA integrates into the E. coli chromosome as a prophage, so both lineages persist while the local arms race is suspended. The lysogenic state is highly stable and remains reversible. A Coercion: Escalation Without End E. coliaction (left) T4 phage response (right) 1.E. colimethylates own DNA 3.E. coliadds restriction enzymes 5.E. colishifts recognition sites 2. T4 evolves unmarked DNA 4. T4 adds anti- restriction proteins 6. T4 evolves new DNA disguises no stable equilibrium other phages B Lysogeny (phage λ): Coordination by Integration E. coli cell bacterial chromosome prophage (integrated phage DNA) phage λ ✓ Both lineages persist ✓ Local arms race suspended ✓ State remains reversible A durable, conditional truce
Figure 45. The TC-Battle and a conditional exit. (A) Coercive control produces an escalating arms race with no stable equilibrium. (B) T4 is strictly lytic. Bacteriophage λ can enter lysogeny, integrating into the host chromosome so both lineages persist in a highly stable state that can return to lysis. After Hofstadter (1979, pp. 532–536); lambda-state qualification from Little and Michalowski (2010).