# E7 — the advantage of sex: recombination adapts faster than clonal reproduction

**Claim tested.** The dynamic mechanism behind E8: *why* can a recombining society reach capability a
lone lineage cannot? Because recombination reassorts beneficial variants that arise in different
sub-lineages, while an asexual (clonal) lineage suffers **clonal interference** — the variants compete
and cannot combine.

**Setup.** A single population (distribution over `2^L` genotypes, `L=12`) adapts from **all-wrong**
toward the multi-locus optimum under the composed step: selection (fitness-proportional) + drift
(resample `n=150`) + mutation (per-locus flips, `μ=0.02`) + recombination. Two arms — **asexual**
(`recomb_rate=0`) vs **sexual** (`recomb_rate=1`). 20 replicates.

### Symbols
- **asexual/clonal** = offspring are whole-genotype copies (Layer-1's regime) · **sexual** = loci reassorted across the population each generation.
- **fitness** = number of correct loci (optimum = `L`) · **linkage disequilibrium |D|** = how far the loci are from statistical independence (correct alleles scattered across different genotypes).

### The two panels
1. **Advantage of sex.** Mean fitness over generations: the **sexual lineage (red) climbs faster**
   than the asexual one (grey) through the adaptation phase (gen ~10–35). *Honest scope:* both plateau
   near the optimum by gen ~40 in this tractable regime — this is a **speed** advantage, not a
   permanent gap (the single-population Muller's ratchet is subtle to force; E8 carries the headline).
2. **Mechanism.** Linkage disequilibrium over generations: the asexual lineage spikes to `|D|≈0.04`
   during adaptation (beneficial alleles held apart, scattered across genotypes), while the sexual
   lineage stays at `|D|≈0` — it *assembles* them. The LD gap is exactly why sexual adapts faster.

### Takeaway
Recombination's advantage is real and classical: it combines good ideas that arose independently,
which clonal reproduction cannot. This is the population-level reason a single evolving model lineage
degrades or stalls where a recombining **society** climbs — and it grounds the E8 vertical result in
the evolution-of-sex theory. **Falsifier (not triggered):** if the sexual lineage adapted no faster
than the asexual one (and kept the same LD), recombination would do no work.