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Gene: Hairy Back
Dad’s alleles: h and h
Mom’s alleles: H and h
Use the
1. Draw dad’s alleles in the appropriate place.
2. Draw mom’s alleles in the appropriate place.
3. What is dad’s genotype?
4. What is dad’s phenotype?
5. What is mom’s genotype?
6. What is mom’s phenotype?
7. Complete the square to find the genotypes of the children. What are these?
8. Which allele is most likely the allele for hairy back?
9. Is this allele dominant or recessive?
10. What is the probability that this couple will have a child with a hairy back?
11. Which of the children’s genotypes is heterozygous?
12. What is the genotype for the other two children?
13. Will this couple ever have a homozygous dominant child? Explain.
14. Could this child have 4 children all with hairy backs? Explain.
15. Under what circumstances will a person have a hairy back?
16.
Show a
17.
Show a
1. A cross between a purebred animal with red hairs and a purebred animal with white hairs produces and animal that has both red hairs and white hairs. What type of inheritance pattern is involved?
2. A red-flowered sweet pea plant is crossed with a white-flowered sweet pea plant. All of the offspring are pink. What is the inheritance pattern being expressed?
Thalessemia is a type of human anemia rather common in the Mediterranean populations, but rare in other people. The disease occurs in two forms, major and minor. Severely affected individuals are homozygous for the gene (TT). Mildly affected individuals are heterozygous (TN). Persons free of the disease are homozygous for the normal gene (NN).
3. A man with Thalessemia minor marries a normal woman. What are the genotypes of their children?
4.
Both father and mother in a particular family have Thalessemia minor.
What is the chance that their baby would be severely affected? Mildly affected?
5. Thelesemmia major is almost always fatal in childhood. An infant has Thalessemia major. What can you expect its parents’ genotypes and phenotypes to be in this case?
1. Cross a white-eyed male fruit fly with a heterozygous red-eyed female. What are the parents’ genes? What gametes will come from each parent? What are the genotype and phenotype ratios of the offspring?
2. Cross a white-eyed male fruit fly with a homozygous red-eyed female. What are the parents’ genes? What gametes will come from each parent? What are the genotype and phenotype ratios of the offspring?
3. A cross between two fruit flies yields a white-eyed female. What would the parents’ genotypes have to be? Use a Punnett square to show your work.
4. In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. Mating of the F1 fish fails to produce females with the trait. Explain a possible inheritance pattern of the trait.
5. If a trait is X-linked, males pass the X-linked allele to __________ of their daughters.
a. All c. none
b. Half d. ¼
6. Most sex-linked traits are passed from mother to __________.