Genetics worksheet with answers

Two Bb parents are crossed. B gives round seeds and is dominant over b, which gives wrinkled seeds. Click the cell of the Punnett square for an offspring with wrinkled seeds.

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

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

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

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 unaffected son.

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

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 unaffected son.

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 shows white 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 500 in Hardy–Weinberg equilibrium, 1 in 2500 show a recessive trait. How many individuals N are expected to be homozygous dominant?