Genetics worksheet with answers

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 has purple flowers?

Two Bb parents are crossed. B gives yellow seeds and is dominant over b, which gives green seeds. Click the cell for an offspring that has yellow seeds and is homozygous.

1. 1B × b
2. 2B × B
3. 3b × b
4. 4b × 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, wrinkled 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

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

In a population of 1000 in Hardy–Weinberg equilibrium, 1 in 1600 show a recessive trait. How many individuals N are expected to be homozygous dominant?