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 of the Punnett square for an offspring with wrinkled seeds.

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 affected 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

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?

A recessive condition affects 4% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

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