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 white flowers?

Two Aa parents are crossed. A gives tall plants and is dominant over a, which gives short plants. Click the cell of the Punnett square for an offspring with short plants.

1. 1A × A
2. 2A × a
3. 3a × A
4. 4a × a

Duchenne muscular dystrophy is X-linked recessive (allele d). A carrier mother, X^DX^d, has children with an unaffected father, X^DY. The mother's gametes run down the side. Click the cell for an affected son.

1. 1X^D × Y
2. 2X^D × X^D
3. 3X^d × Y
4. 4X^d × X^D

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 1% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

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

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