Question

In the shrub Ixococ meloites, red flower color is incompletely dominant to white flower color. If a true-breeding plant with red flowers is crossed to a true breeding plant with white flowers, what would be the phenotype of the F1 plants? a. The plants will all have red flowers. b. The plants will all have white flowers. c. The some of the flowers on an F1 plant will be red and other flowers on the same plant will be white. d. All of the flowers will be pink (whitish red). e. All of the flowers will be green. If you perform a genetic cross and you find that 1% of the offspring show recombination between genes A and B; but 15% of the offspring show recombination between genes B and C. Which of the statements below is true: a. Gene C controls the expression of gene B. b. Gene C controls the expression of gene A. c. Gene A is epistatic to gene B. d. Genes A and B are likely physically closer together on the same chromosome than genes B and C. e. Genes B and C are likely physically closer together on the same chromosome than genes A and B.

3. From the data in the above cross, you want to construct a genetic map, to position genes A, B, C and D on a chromosome. Therefore you also obtain additional genetic information from the cross in the previous question. You find 14% of the offspring show recombination between genes A and C; 16% show recombination between genes A and D; 17% show recombination between genes B and D; and 2% show recombination between genes C and D. Based on this information and the data from the previous question, what is the order of the four genes A, B, C and D on the chromosome?

	a.	A-B-C-D.
	b.	A-C-B-D.
	c.	B-A-C-D.
	d.	B-C-A-D.
	e.	B-D-A-C.

4. If the F1 generation plants from question 19 above are crossed to themselves (selfed), what percentage of the F2 plants will have red flowers?

	a.	0%.
	b.	25%.
	c.	50%.
	d.	75%.
	e.	100%.

5. Given the information from question 4, if a heterozygous female (a carrier of color blindness, but not color blind herself) has children with a normal man, what percentage of the female progeny (children) will be color blind?

	a.	0%.
	b.	25%.
	c.	50%.
	d.	75%.
	e.	100%.

2

Given the information from question 4, if a heterozygous female (a carrier of color blindness) has children with a normal man, what percentage of the male progeny will be color blind?

	a.	0%.
	b.	25%.
	c.	50%.
	d.	75%.
	e.	100%.

Given the information from question 4, if a heterozygous female (a carrier of color blindness) has children with a normal man, what percentage of the female progeny will be carriers of the color blindness allele?

	a.	0%.
	b.	25%.
	c.	50%.
	d.	75%.
	e.	100%.

Answer 1

Answer.1. (d) all of the flower will be pink

Incomplete dominance - neither allele is dominant over the other. Example - 4'O clock plant

Answer 2. (d) Genes A and B are likely physically closer together on the same chromosome than genes B and C

Closely related genes have low recombination frequency

Answer 3.(C) B-A-C-D

Answer 4. (B) 25%

Answer 5. (a) 0%

Answer 6. (B) 25% male color blind

Answer 7. (B) 25% carrier