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 Aa parents are crossed. A gives black fur and is dominant over a, which gives white fur. Click the cell of the Punnett square for an offspring with white fur.

1. 1A × a
2. 2A × A
3. 3a × a
4. 4a × A

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 a carrier daughter.

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 unaffected 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 400 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

In a population of 1000 in Hardy–Weinberg equilibrium, 4% show a recessive trait. How many individuals N are expected to be homozygous dominant?