Genetics worksheet with answers

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

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

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)?

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?

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

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

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 10000 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?