In guinea pigs, the allele for black fur, BBB, is dominant to the allele for white fur, bbb.
A breeder has a male guinea pig with black fur. She wants to find out the genotype of this male.
She crosses the male with a female guinea pig with white fur.
Give the two possible genotypes of the male guinea pig.
Explain why the breeder crossed the male with a female with white fur.
The cross produced 4 offspring with black fur and 3 offspring with white fur.
Explain what these results show about the genotype of the male guinea pig.
Use a genetic diagram in your answer.
43 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.