CAPE Biology Unit 1 · 2014 · Paper 1 · Question Q22

Items 22–23 refer to the following information. A particular breed of domestic cats can have either black, white or brown fur colour. The dominant allele, B, of one gene gives black fur and the recessive allele, b, gives brown fur. Many of the white cats carry a dominant allele, P, of a second gene which inhibits all pigment production. The recessive allele, p, has no effect on the colour of the fur. The two different genes are not linked nor are they on the X chromosome. This type of gene interaction is described as

1. (A)epistasis
2. (B)sex-linkage
3. (C)codominance
4. (D)dominant/recessive