Genetics worksheet with answers

Two Tt parents are crossed. T gives tall plants and is dominant over t, which gives short plants. Click the cell for an offspring that has tall plants and is homozygous.

1. 1t × T
2. 2t × t
3. 3T × T
4. 4T × t

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?

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 unaffected son.

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

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

In a population of 500 in Hardy–Weinberg equilibrium, 16% show a recessive trait. How many individuals N are expected to be homozygous dominant?

A recessive condition affects 1 in 400 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?