Genetics worksheet with answers

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

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)?

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, round 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 affected son.

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

A recessive condition affects 1 in 10000 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

A recessive condition affects 9% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?