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 affected father, X^hY. The mother's gametes run down the side. Click the cell for an affected daughter.

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 affected 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

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

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

A recessive condition affects 1 in 2500 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?