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

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?

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?

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 an affected son.

1. 1X^D × X^D
2. 2X^D × Y
3. 3X^d × X^D
4. 4X^d × Y

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