Genetics worksheet with answers

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

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

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 is heterozygous (Aa)?

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 son.

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

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 tall, wrinkled seeds?

In a population of 10000 in Hardy–Weinberg equilibrium, 1 in 10000 show a recessive trait. How many individuals N are expected to be homozygous dominant?

In a population of 500 in Hardy–Weinberg equilibrium, 1% show a recessive trait. How many individuals N are expected to be homozygous dominant?