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 is heterozygous (Aa)?

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

1. 1R × r
2. 2R × R
3. 3r × r
4. 4r × R

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an affected father, X^hY. The mother's gametes run down the side. Click the cell for an affected son.

1. 1X^h × X^h
2. 2X^h × Y
3. 3X^H × X^h
4. 4X^H × Y

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 1 in 2500 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

Two AaBb parents are crossed. Gene A gives tall plants (dominant) or short plants; gene B gives black fur (dominant) or white fur. Click the one cell for an offspring that is homozygous for tall plants 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