In a species of beetle, wing cases may be spotted or unspotted. Beetles with at least one copy of allele S have spotted wing cases. The unspotted phenotype is only seen in beetles with two copies of allele s.
Two beetles with spotted wing cases produced 100 offspring.
| Offspring phenotype | Number of offspring |
|---|---|
| Spotted wing cases | 74 |
| Unspotted wing cases | 26 |
Explain what the results show about the genotype of each parent.
Calculate the expected percentage of offspring with unspotted wing cases if the same cross is repeated many times.
62 exam-style questions on AQA GCSE Biology 6.1 Reproduction, covering 6.1.1 Sexual and asexual reproduction, 6.1.2 Meiosis, 6.1.3 Advantages and disadvantages of sexual and asexual reproduction, 6.1.4 DNA and the genome, 6.1.5 DNA structure, 6.1.6 Genetic inheritance, 6.1.7 Inherited disorders, and 6.1.8 Sex determination. Each one has a worked solution and a mark scheme showing where the marks go.