Genetics Review

Honors Bio 2011

Which parents would you expect to give only one phenotype?

AaBb x aabb

AaBb x AABB

AaBb x AaBb

AaBb x AAbb

0% 0%

16%

84%1. AaBb x aabb2. AaBb x AABB3. AaBb x AaBb4. AaBb x AAbb

Which parents would you expect to give a 9:3:3:1 ratio of phenotypes?

AaBb x aabb

AaBb x AABB

AaBb x AaBb

AaBb x AAbb

22%17%

61%

0%

1. AaBb x aabb2. AaBb x AABB3. AaBb x AaBb4. AaBb x AAbb

Which parents would you expect to give a 1:1:1:1 ratio of phenotypes?

AaBb x aabb

AaBb x AABB

AaBb x AaBb

AaBb x AAbb

74%

26%

0%0%

1. AaBb x aabb2. AaBb x AABB3. AaBb x AaBb4. AaBb x AAbb

Which parents would you expect to give only two phenotypes (50 % each)?

AaBb x aabb

AaBb x AABB

AaBb x AaBb

AaBb x AAbb

0%

89%

5%5%

1. AaBb x aabb2. AaBb x AABB3. AaBb x AaBb4. AaBb x AAbb

Which of the following statements are true about sex-linked traits?

Since

they are

...

Since

they are

...

Are m

ore lik

el...

Are m

ore lik

el...

More

than one...

0% 0%

33%

61%

6%

1. Since they are on the X chromosome, they are only expressed in females.

2. Since they are on the X chromosome, they are only expressed in males.

3. Are more likely to appear in the phenotypes of females.

4. Are more likely to appear in the phenotypes of males.

5. More than one answer is correct

In garden peas, yellow seed color is dominant over green. A cross between a homozygous yellow plant and a homozygous

green plant yields 25 plants. If an F1 cross were performed and 40 plants were produced, how many of the F2 plants would you

expect to be yellow?

1012.5 20 25 30 40

17%

6%

22%

33%

11%11%

1. 102. 12.53. 204. 255. 306. 40

Regions marked A and B are genes. “A” results in the production of purple flowers. “B” results in the production of white flowers. Which term best describes these different flower color genes?

0%

100%

0%

0%

A

B

1. Homozygous2. Dominant3. Alleles4. Recessive

Based on this Punnett square, what percentage of offspring would be homozygous?

25%50%

75%100%

0% 0%0%

100%

B B

B

b

1. 25%2. 50%3. 75%4. 100%

Cattle have red, roan, & white coat colors. When a red bull and white cow mate, a roan color, which is a “mixture” of red & white, is produced. What is this

an example of? 100%

0%0%0%

1. Codominance2. Sex-linked genes3. Autosomal recessive

traits4. Pedigrees

A cross is made between two parents with the genotypes AaBB and aabb. If there are 32 offspring,

how many of them would be expected to be heterozygous for both characteristics?

6%

69%

13%

13% 1. 322. 243. 164. 8

Below is a pedigree showing red-green color-blindness, a recessive sex-linked trait in a family. What is the genotype of the individual indicated by the arrow?

0%

68%

26%

5% 1. XH Xh 2. Xh Y3. XH Y4. Xh Xh

In toucans, yellow beak color (Y) is dominant over green beak color and long feathers (L) are dominant over short. A male

toucan with a green beak and long feathers mates with a female with a yellow beak and long feathers. They have offspring with green beaks and short feathers. What are the genotypes of the

parents?

0%

0%

0%

100% 1. yyLl x YyLl2. YyLl x YyLl3. yyll x YYLL4. Yyll x yyLL

If the person that is the arrow is pointing to marries a female who is homozygous dominant, what is the

possibility that they will have a daughter that carries the red-green colorblindness gene?

67%

22%

11%

0% 1. 0%2. 25%3. 50%4. 100%

A man with a blood type A marries a woman with blood type B. Their first child has type O blood. What is the possibility that they could have another child

with blood type O?

0%25%

50%75%

100%

6%

83%

6%0%

6%

1. 0%2. 25%3. 50%4. 75%5. 100%

In roses, red color is dominant over yellow color. A cross between a homozygous red rose and a

homozygous yellow rose yields 80 heterozygous roses. A cross between two of these heterozygous

roses yields 160 F2 roses. How many of these F2 roses are expected to be red?

0%

78%

17%

6% 1. 402. 803. 1204. 160

When a blue sea sponge mates with yellow sea sponge, a beautiful shade of green sea sponge is

produced. What is this an example of?

6%

94%

0%0%

1. Codominance2. Dihybrid crosses3. Inbreeding4. Incomplete

dominance

Based on this Punnett square, what percentage of offspring would express the recessive trait?

25%50%

75%100%

95%

0%5%

0%

B b

B

b

1. 25%2. 50%3. 75%4. 100%

In spiders eight legs is due to a dominant allele (E). Hairy bodies on spiders are due to another dominant allele (H). If a

male who has both conditions (EeHh) mates with a female with both (EeHh), what are the chances of an offspring having

only one of the two dominant traits?

0%

12%

65%

24%

0%1. 1/162. 3/163. 6/164. 9/165. 16/16