Genetics worksheet with answers

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

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

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 white flowers?

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?

haemophilia is X-linked recessive (allele h). A carrier mother, X^HX^h, has children with an unaffected father, X^HY. The mother's gametes run down the side. Click the cell for an affected son.

1. 1X^H × X^H
2. 2X^H × Y
3. 3X^h × X^H
4. 4X^h × Y

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

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