Allele key:
AAA: amber fins, dominant
aaa: plain fins, recessive
A plain-finned fish is crossed with an amber-finned fish. The table shows the phenotypes of their offspring.
| Offspring phenotype | Number |
|---|---|
| Amber fins | 12 |
| Plain fins | 11 |
Explain what the results show about the genotype of the amber-finned parent.
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.