In a species of bird, feather colour is controlled by one gene with three alleles: CRC^RCR, CY C^Y\,CY and ccc. The allele CR C^R\,CR gives red feathers, the allele CY C^Y\,CY gives yellow feathers and the allele c c\,c gives white feathers.
The alleles CR C^R\,CR and CY C^Y\,CY are codominant. Both are dominant to ccc.
A bird with red and yellow patches is crossed with a bird with yellow feathers. One of their chicks has red feathers.
Explain why the parent with yellow feathers must have the genotype CYcC^Y cCYc.
Calculate the probability that another chick from these two parents will have red and yellow patches.
71 exam-style questions on Edexcel GCSE Biology 3.3 Inheritance, covering 3.3.1 Gregor Mendel and the basis of genetics, 3.3.2 Alleles and inherited characteristics, 3.3.3 Monohybrid inheritance, 3.3.4 Determination of sex at fertilisation, 3.3.5 Outcomes from monohybrid crosses, 3.3.6 Inheritance of ABO blood groups, 3.3.7 Inheritance of sex-linked disorders, and 3.3.8 Multiple genes and phenotypic features. Each one has a worked solution and a mark scheme showing where the marks go.