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 white flowers?

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 an unaffected son.

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 homozygous for purple flowers and shows white 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

In a population of 500 in Hardy–Weinberg equilibrium, 4% show a recessive trait. How many individuals N are expected to be homozygous dominant?