Trace DNA copying without assuming balanced inheritance

Define the evidence

Semiconservative copying gives each daughter DNA duplex one template strand and one newly synthesized strand. DNA polymerases extend a new strand in the 5′ to 3′ direction by adding to its 3′ end. At a moving replication fork, antiparallel templates therefore require continuous leading-strand synthesis and discontinuous lagging-strand fragments. Priming provides an extendable end; ligation joins processed fragments. These molecular roles are not a method for replicating or engineering a microorganism.

Connect mechanism and measurement

A typical bacterial circular chromosome initiates copying at an origin and proceeds bidirectionally, but bacterial chromosomes, archaeal replication systems, eukaryotic nuclei and plasmids are not interchangeable. Multiple replication rounds or chromosome copies can make DNA content per cell differ from a simple one-chromosome picture. Copy number, chromosome organization and allocation must be specified rather than inferred from the word bacterium.

The original ledger begins with exactly one duplex, applies g complete rounds to every duplex without loss, then assigns the resulting DNA to two conceptual pools. There are 2^g duplexes and 2^(g+1) strands. Only two strands were present initially, so their fraction among all strands is 2^(−g). This distinguishes preservation of original strands from preservation of an intact original duplex.

The final allocation is deliberately independent of the copying rule: one pool receives 2^(g−1)+d duplexes and the other 2^(g−1)−d. Unequal allocation conserves total DNA but does not provide equal inheritance. We do not claim these pools are viable daughter cells or infer which pool contains each original strand. Actual segregation mechanisms and cell-cycle evidence would be needed.

Reconstruct the original record

After three complete rounds, eight duplexes contain sixteen strands, only two of which are original. Their strand fraction is 1/8. A redistribution of one duplex gives pools of five and three, still totaling eight; the unequal pools do not contradict semiconservative copying.

Predict and investigate

Predict first: Can every strand be accounted for while the final DNA pools remain unequal?

Reconstruct duplex and strand totals, then change allocation without changing copying rounds. Separate the conservation statement from a claim about equal daughter inheritance and identify what the ledger does not locate.

Defend a changed case

Apply the mechanism to a changed boundary

Use four rounds and redistribution of two duplexes. Find both pools, total new strands and original-strand fraction.

Retain the first response, units, uncertainty and any prior feedback exposure in the notebook before comparing this public explanation.

Compare a worked response

There are sixteen duplexes, split ten and six. Thirty-two strands include two original and thirty new strands; the original fraction is 1/16. The original strands are not assigned to specific pools by this model.

Retain bounded evidence

Preserve original assumptions, first responses and feedback exposure in the Microbiology evidence workspace. All numerical records are original fictional evidence. No culture, genetic modification, transfer execution, resistance generation or personal clinical interpretation is requested. Actual independent practical competence is not established.

Primary mechanism context, checked 30 October 2026. Original teaching and fictional data; no copied operating procedures.