Genetics worksheet with answers

Two Rr parents are crossed. R gives round seeds and is dominant over r, which gives wrinkled seeds. Click the cell for an offspring that has round seeds and is homozygous.

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

Two Aa parents are crossed. A gives tall plants and is dominant over a, which gives short plants. Click the cell of the Punnett square for an offspring with short plants.

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

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.

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

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?

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

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

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