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 is heterozygous (Aa)?

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, wrinkled seeds?

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 an unaffected son.

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

In a population of 2000 in Hardy–Weinberg equilibrium, 1 in 2500 show a recessive trait. How many individuals N are expected to be homozygous dominant?

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