In guinea pigs, the allele for black fur (B) is dominant to the allele for white fur (b).
A breeder crosses a heterozygous male with black fur and a female with white fur.
The Table shows a Punnett square for this cross. The gametes of the male are shown across the top. The gametes of the female are shown down the side.
Table
| B | b | |
|---|---|---|
| b | ||
| b |
Give the genotype of the female with white fur.
Complete the Punnett square in the Table to show the genotypes of the offspring.
Give the probability that an offspring from this cross has white fur.
The guinea pigs have 8 offspring. 3 offspring have black fur and 5 have white fur.
Explain why these numbers are not the same as the expected ratio.
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.