Genetics worksheet with answers

Two Bb parents are crossed. B gives round seeds and is dominant over b, which gives wrinkled seeds. Click the cell for an offspring that has round seeds and is homozygous.

1. 1b × b
2. 2b × B
3. 3B × b
4. 4B × B

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

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

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 daughter.

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

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 daughter.

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

A recessive condition affects 16% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

In a population of 10000 in Hardy–Weinberg equilibrium, 4% show a recessive trait. How many individuals N are expected to be homozygous dominant?