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

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

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

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

1. 1X^h × X^h
2. 2X^h × Y
3. 3X^H × X^h
4. 4X^H × Y

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

A recessive condition affects 4% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?