The flower colour of a particular species of plant is determined by a single gene with three alleles that show codominance and simple dominance.
The table below shows the different flower phenotypes and their genotypes:
| Flower phenotype | Genotypes |
|---|---|
| Red | CRCR C^R C^R\,CRCR or CRCWC^R C^WCRCW |
| Blue | CBCB C^B C^B\,CBCB or CBCWC^B C^WCBCW |
| Purple | CRCBC^R C^BCRCB |
| White | CWCWC^W C^WCWCW |
Explain what is meant by the term codominance.
A cross between a red-flowered plant and a blue-flowered plant produces some offspring with white flowers. Use a genetic diagram to show how this is possible. Your diagram should include:
66 exam-style questions on Edexcel IGCSE Biology Inheritance. Each one has a worked solution and a mark scheme showing where the marks go.