Wing-case pattern in a species of beetle is controlled by one gene.
| Allele | Description |
|---|---|
| SSS | dominant allele associated with striped wing cases |
| sss | recessive allele associated with plain wing cases |
A beetle with striped wing cases is crossed with a beetle with plain wing cases. The plain parent has genotype ssssss.
| Phenotype of offspring | Number of offspring |
|---|---|
| Striped wing cases | 8 |
| Plain wing cases | 8 |
State the genotype of the striped parent and explain your answer.
Calculate the expected number of offspring with plain wing cases if the same two beetles produce 60 offspring.
186 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.