Genetics worksheet with answers

Two Aa parents are crossed. A gives black fur and is dominant over a, which gives white fur. Click the cell for an offspring that has black fur and is homozygous.

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

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

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 short, 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 × Y
2. 2X^H × X^H
3. 3X^h × Y
4. 4X^h × X^H

Two AaBb parents are crossed. Gene A gives round seeds (dominant) or wrinkled seeds; gene B gives black fur (dominant) or white fur. Click the one cell for an offspring that is homozygous for round 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 1000 in Hardy–Weinberg equilibrium, 1 in 1600 show a recessive trait. How many individuals N are expected to be homozygous dominant?