Genetics worksheet with answers

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

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an unaffected father, X^HY. The mother's gametes run down the side. Click the cell for an affected son.

1. 1X^H × X^H
2. 2X^H × Y
3. 3X^h × X^H
4. 4X^h × 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, wrinkled seeds?

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 homozygous for black fur and 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 400 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?