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 is heterozygous (Aa)?

Two Bb parents are crossed. B gives yellow seeds and is dominant over b, which gives green seeds. Click the cell for an offspring that has yellow seeds and is homozygous.

1. 1B × B
2. 2B × b
3. 3b × B
4. 4b × b

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 a carrier daughter.

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 tall, wrinkled seeds?

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

In a population of 500 in Hardy–Weinberg equilibrium, 9% show a recessive trait. How many individuals N are expected to be homozygous dominant?