Genetics worksheet with answers

Two Bb parents are crossed. B gives yellow seeds and is dominant over b, which gives green seeds. Click the cell for an offspring that has yellow seeds and is homozygous.

1. 1b × b
2. 2b × B
3. 3B × b
4. 4B × B

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?

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

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 tall, round seeds?

Two AaBb parents are crossed. Gene A gives purple flowers (dominant) or white flowers; gene B gives round seeds (dominant) or wrinkled seeds. Click the one cell for an offspring that is shows both white flowers and wrinkled 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 4% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?