Genetics worksheet with answers

Two Tt parents are crossed. T gives round seeds and is dominant over t, which gives wrinkled seeds. Click the cell of the Punnett square for an offspring with wrinkled seeds.

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

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

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

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an unaffected 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

red-green colour blindness is X-linked recessive (allele b). A carrier mother, X^BX^b, has children with an affected father, X^bY. The mother's gametes run down the side. Click the cell for an affected daughter.

1. 1X^b × X^b
2. 2X^b × Y
3. 3X^B × X^b
4. 4X^B × Y

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

A recessive condition affects 1 in 1600 of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?