Genetics worksheet with answers

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

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

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

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

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, round seeds?

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

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

Two AaBb parents are crossed. Gene A gives tall plants (dominant) or short plants; gene B gives black fur (dominant) or white fur. Click the one cell for an offspring that is homozygous for tall plants and for black fur.

1. 1Ab × aB
2. 2Ab × ab
3. 3Ab × AB
4. 4Ab × Ab
5. 5aB × aB
6. 6aB × ab
7. 7aB × AB
8. 8aB × Ab
9. 9AB × aB
10. 10AB × ab
11. 11AB × AB
12. 12AB × Ab
13. 13ab × aB
14. 14ab × ab
15. 15ab × AB
16. 16ab × Ab