In a species of fish, striped scales (SSS) are dominant to plain scales (sss). A striped fish is crossed with a fish that has plain scales. The plain-scaled fish is homozygous recessive. The offspring are recorded in the table.
| Offspring phenotype | Number of fish |
|---|---|
| Striped scales | 42 |
| Plain scales | 38 |
Use the results to suggest the genotype of the striped-scaled parent. Explain your answer.
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.