Challenge a unique explanation for heterozygote deficiency

1. Orient: Challenge a unique explanation for heterozygote deficiency

Nonrandom mating changes which allele copies pair in individuals. Inbreeding increases the probability of identity by descent relative to a specified reference population. It is not synonymous with a rare allele, a low census count or a unique molecular defect. Population structure can also alter aggregate genotype proportions.

2. Explain the population mechanism

The supplied two-allele model uses AA=p²+Fpq, Aa=2pq(1−F), aa=q²+Fpq. The added Fpq in each homozygote class exactly balances the removed2Fpq heterozygotes. Recounting A gives p: this isolated mating-structure step redistributes genotypes without itself changing allele frequency.

A distinct pooled-sample example mixes equal numbers from two random-mating populations at p0.2 and0.8. Each has heterozygosity0.32; the pool therefore also has0.32, although pooled p0.5 predicts0.5 under random union across the pool. This Wahlund-effect deficit arises because the pooled reference ignores population structure, not because either constituent must be inbred.

An observed deficit can reflect multiple causes, including sampling, scoring, mating structure or stage-specific selection. A single F-like summary is not a unique diagnosis. Retain location, relatedness, sampling stage and assay quality; compare within meaningful populations before making biological claims. No personal ancestry or clinical inference is requested.

3. Work a complete evidence calculation

At p0.4,F0.5, pq0.24 gives AA0.16+0.12=0.28,Aa0.24,aa0.36+0.12=0.48. Recounted p=0.28+0.12=0.4. The genotype distribution changed, but the allele frequency did not.

4. Predict and investigate

Predict first: Can a pooled heterozygote deficit occur even if every constituent population mates randomly?

Vary F at fixed p0.4 and track the complete genotype inventory and recounted allele frequency. Then independently calculate the equal mixture of p0.2 and0.8 populations. Propose stratified sampling that distinguishes pooled structure from a within-population deficit.

Retain the original population definition, first prediction, controls and full numerical ledger, including conflicting or null results. These are original bounded teaching calculations, not measured populations.

5. Transfer and explain

Apply the mechanism to a changed case

At p0.5,F0.25, calculate the three genotype frequencies and the allele frequency.

Retain your calculation, units and assumptions in the lesson notebook before opening this public practice response.

Compare a worked response

AA0.25+0.0625=0.3125,Aa0.5×0.75=0.375,aa0.3125. Recounted p0.3125+0.1875=0.5. Increased homozygosity need not imply allele-frequency change.

6. Reflect and retain evidence

State a competing mechanism, an observation that would distinguish it, and a limitation of the supplied sampling or life-cycle model. Preserve first reasoning and a criterion-linked human review in the General Biology II workspace. Public practice feedback and simulated evidence do not certify an independently demonstrated comparative argument, field investigation or practical skill.

Supporting scientific reference, checked 30 October 2026. All prose, numerical packets and diagrams are original. No organism collection, culture, breeding, release, personal genetic inference or clinical procedure is requested.