SBI3U
Multiple Alleles (plus others)
1. If a man with blood type A, one of whose parents had blood type 0, marries a woman with blood type AB, one of whose parents has blood type B, what will be the theoretical percentage of their children with blood type A?
2. A man has blood type A and his wife has blood type B. A child has blood type O. Could these individuals be the parents of this child? explain.
3. In foxes, a pair of alleles, P and p interact as follows: PP is lethal, usually killing the embryo ; Pp produces platinum-coloured fur, and pp produces silver foxes. Could a fox-breeder establish a pure-breeding strain of platinum foxes (ie: could he produce a breeding pair whose offspring would always be platinum coloured) Explain your answer.
4. If a man with blood type A, one of whose parents had blood type 0, marries a woman with blood type AB, one of whose parents has blood type B, what will be the theoretical percentage of their children with blood type A?
5. A mother with blood type AB has a child with the same blood type. What are the possible blood types of the father?
6. Two women, Mrs Roe and Mrs Doe had babies at the same hospital at the same time. Mrs. Doe took home a girl and named her Nancy , Mrs Roe took home a boy and named him Richard. However, Mrs. Roe was sure she had had a girl and she sued the hospital. Blood tests showed that Mrs. Roe was blood type O and Mr. Roe was blood type AB. Mr and Mrs. Doe were both type B. Nancy was blood type A and Richard was blood type O. Had an exchange occurred? Explain your answer.
7. Feather colour is co-dominant in some varieties of chickens, with Black individuals expressing the dominant B allele and White individuals expressing the dominant W allele. Heterozygous dominant chickens are black and white checked feathers. There are no recessive alleles for this colour in this case. If a checked bird is crossed with a white bird, what are the expected genotypic and phenotypic ratios of the chicks?
8. a. A woman sues a man for support of her child. She has blood type A. Her child has blood type O and the man has blood type B. Could the man be the father? Explain your answer.
b. The man checks his family history and determines that both his parents have blood type AB. Does he now have an argument?
9. Coat colour in rabbits is determined by four different alleles. Each allele is responsible for
producing a different coat colour: dark grey, Chinchilla, Himalayan, and white. Each rabbit has only two alleles. Study the relationship among the alleles in the table
phenotype / allele / pattern of inheritanceDark Grey / C / dominant to all other alleles
Chinchilla / cch / dominant to Himalayan and white
Himalayan / ch / dominant to white
white / c / recessive
(i) List all of the possible genotypes for
(a) dark grey rabbit
(b) Chinchilla rabbit
(c) Himalayan rabbit
(d) white rabbit
(ii) Predict the phenotype of a rabbit with the following genotypes.
(a) ch cch (b) C ch
(iii) Would it be possible to obtain white rabbits if one of the parents is white and the other is Chincilla? (explain)
(iv) Would it be possible to obtain Chinchilla rabbits if one parent is Himalayan and the other is white? (explain)
(v) A Chinchilla rabbit is mated with a Himalayan. Some of the offspring are white. What are the parents’ genotypes?