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 purple flowers?

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

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

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

In a population of 5000 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 round seeds (dominant) or wrinkled seeds; gene B gives black fur (dominant) or white fur. Click the one cell for an offspring that is homozygous for round seeds and for black 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