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 purple flowers?

red-green colour blindness is X-linked recessive (allele b). A carrier mother, X^BX^b, has children with an affected father, X^bY. The mother's gametes run down the side. Click the cell for an affected daughter.

1. 1X^b × Y
2. 2X^b × X^b
3. 3X^B × Y
4. 4X^B × X^b

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

In a population of 5000 in Hardy–Weinberg equilibrium, 1% show a recessive trait. How many individuals N are expected to be homozygous dominant?

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 homozygous for purple flowers 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