Single answerDifficulty 4/5 · HardOlympiadStatistical analysisArgumentation
Too few heterozygotes
A biologist sampled 400 hermaphroditic land snails from one large colony and used gel electrophoresis to score an enzyme gene with two codominant alleles, F (fast band) and S (slow band). Because the alleles are codominant, every genotype can be counted directly. These snails can self-fertilise when mates are scarce.
Data
| Genotype | Number of snails |
|---|---|
| FF | 150 |
| FS | 140 |
| SS | 110 |
| Total | 400 |
Calculate the allele frequencies and expected genotype counts, then carry out a χ² test (1 degree of freedom; critical value 3.84 at p = 0.05). Which conclusion is best supported?
Answer every part to submit.