Genetics worksheet with answers

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

1. 1R × R
2. 2R × r
3. 3r × R
4. 4r × r

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?

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, wrinkled 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 affected 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 black fur (dominant) or white fur; gene B gives round seeds (dominant) or wrinkled seeds. Click the one cell for an offspring that is shows white fur 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

A recessive condition affects 1 in 1600 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?