Biology 9700 · AS & A Level · Passage of information from parents to offspring
Passage of information from parents to offspring — practice question
In mice, the degree of fur pigmentation is determined by several alleles of one gene. These alleles are arranged in dominance order, with $C$ the most dominant: $C$ = full colour, $C^{ch}$ = chinchilla, $C^{h}$ = himalayan, $C^{p}$ = platinum, $C^{a}$ = albino.
(a)[2]
Explain how multiple alleles come about.
(b)[6]
In mice, eye colour is determined by two alleles of one gene, $B/b$: allele $B$ gives black eyes and allele $b$ gives red eyes. A mouse with full colour fur and black eyes was crossed with a mouse with himalayan fur and black eyes. One offspring was albino with red eyes. Using the symbols above, draw a genetic diagram to show the genotypes and phenotypes of the offspring from this cross.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Gene mutation means a change in base or nucleotide sequence” …