Genetics worksheet with answers

In pea plants, purple flowers (A) are dominant over white (a). A plant with genotype Aa is crossed with a plant with genotype Aa. What is the probability P that an offspring has purple flowers?

Two Tt parents are crossed. T gives purple flowers and is dominant over t, which gives white flowers. Click the cell of the Punnett square for an offspring with white flowers.

1. 1t × t
2. 2t × T
3. 3T × t
4. 4T × T

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an unaffected father, X^HY. The mother's gametes run down the side. Click the cell for an unaffected son.

1. 1X^H × X^H
2. 2X^H × Y
3. 3X^h × X^H
4. 4X^h × Y

Tall (A) is dominant over short (a), and round seeds (B) over wrinkled (b). The genes are on different chromosomes. For the cross AaBb × Aabb, what is the probability P that an offspring is short, round seeds?

A recessive condition affects 4% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

Two AaBb parents are crossed. Gene A gives black fur (dominant) or white fur; gene B gives purple flowers (dominant) or white flowers. Click the one cell for an offspring that is shows both white fur and white flowers.

1. 1Ab × Ab
2. 2Ab × aB
3. 3Ab × ab
4. 4Ab × AB
5. 5aB × Ab
6. 6aB × aB
7. 7aB × ab
8. 8aB × AB
9. 9ab × Ab
10. 10ab × aB
11. 11ab × ab
12. 12ab × AB
13. 13AB × Ab
14. 14AB × aB
15. 15AB × ab
16. 16AB × AB