Genetics worksheet with answers

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?

Two Rr parents are crossed. R gives round seeds and is dominant over r, which gives wrinkled seeds. Click the cell for an offspring that has round seeds and is homozygous.

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

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

1. 1X^b × X^B
2. 2X^b × Y
3. 3X^B × X^B
4. 4X^B × 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 short, round seeds?

Two AaBb parents are crossed. Gene A gives round seeds (dominant) or wrinkled seeds; gene B gives purple flowers (dominant) or white flowers. Click the one cell for an offspring that is shows both wrinkled seeds and white flowers.

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

Two AaBb parents are crossed. Gene A gives black fur (dominant) or white fur; gene B gives yellow seeds (dominant) or green seeds. Click the one cell for an offspring that is homozygous for black fur and for yellow 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