Genetics worksheet with answers

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

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

Two Aa parents are crossed. A gives tall plants and is dominant over a, which gives short plants. Click the cell of the Punnett square for an offspring with short plants.

1. 1a × a
2. 2a × A
3. 3A × a
4. 4A × A

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?

Duchenne muscular dystrophy is X-linked recessive (allele d). A carrier mother, X^DX^d, has children with an affected father, X^dY. The mother's gametes run down the side. Click the cell for an unaffected son.

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 tall plants (dominant) or short plants; gene B gives purple flowers (dominant) or white flowers. Click the one cell for an offspring that is homozygous for tall plants and for purple 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

In a population of 500 in Hardy–Weinberg equilibrium, 1 in 10000 show a recessive trait. How many individuals N are expected to be homozygous dominant?