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)?

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?

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

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

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 green seeds and is homozygous for round 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 5000 in Hardy–Weinberg equilibrium, 4% show a recessive trait. How many individuals N are expected to be homozygous dominant?