Genetics worksheet with answers

Free printable Genetics worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy

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)?

Aa × AA

P =

2.Easy

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)?

Aa × aa

P =

3.Medium

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

♀ X^BX^b♂ X^BY

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

4.Medium

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?

AaBb × Aabb

P =

5.Hard

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

q² = 0.000625

f =

6.Hard

A recessive condition affects 9% of a population in Hardy–Weinberg equilibrium. What fraction f of the population are carriers (heterozygous)?

q² = 0.09

f =

Answer key

1. P = 0.5
2. P = 0.5
3. X^b × Y
4. P = 0.125
5. f = 0.04875
6. f = 0.42

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