Biology 9700 · AS & A Level · Passage of information from parents to offspring

Passage of information from parents to offspring — practice question

A wide range of genes contributes to pigment production in mammals. One example is the TYR gene.
(a(i))[1]

Homologous chromosomes carry the same genes at the same loci. State one further feature that homologous chromosomes share.

(a(ii))[3]

In humans, albinism can result from recessive mutations in the TYR gene. Explain why a person who is homozygous recessive for the TYR gene shows albinism.

(b)[4]

Complete the genetic diagram for a cross between two black rabbits that are heterozygous for both genes, and show the ratio of the possible offspring phenotypes.

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