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 of the Punnett square for an offspring with short plants.

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

Two Rr parents are crossed. R gives yellow seeds and is dominant over r, which gives green seeds. Click the cell of the Punnett square for an offspring with green seeds.

1. 1r × R
2. 2r × r
3. 3R × R
4. 4R × r

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

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?

A recessive condition affects 4% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

In a population of 500 in Hardy–Weinberg equilibrium, 4% show a recessive trait. How many individuals N are expected to be homozygous dominant?