Test Bank For An Introduction To Genetic Analysis 11th Edition BY GRIFFITHS

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Test Bank For An Introduction To Genetic Analysis 11th Edition BY GRIFFITHS

Chapter 3 Independent Assortment of Genes

MULTIPLE-CHOICE QUESTIONS 

Sections 3.1 and 3.2. (Mendel’s law of independent assortment, Working with independent assortment)

1. Mendel crossed Y/Y;R/R (yellow wrinkled) peas with y/y;r/r (green smooth) peas and selfed the F₁ to obtain an F₂. In the F₂ what proportion of the yellow wrinkled individuals were pure-breeding?

 A) 1/9

 B) 3/16

 C) 1/4

 D) 3/4

 E) 9/16

Answer: A

2. Mendel crossed Y/Y;R/R (yellow wrinkled) peas with y/y;r/r (green smooth) peas and selfed the F₁ to obtain an F₂. What proportion of the F₂ individuals were pure-breeding?

 A) 1/9

 B) 3/16

 C) 1/4

 D) 3/4

 E) 9/16

Answer: C

3. If genes assort independently, a testcrossed dihybrid characteristically produces progeny phenotypes in the ratio:

 A) 1:1

 B) 1:1:1:1

 C) 1:2:1

 D) 3:1

 E) 9:3:3:1

Answer: B

4. A fish of genotype a/a; B/b is crossed to a fish whose genotype is A/a; B/b. What proportion of the progeny will be heterozygous for at least one of the genes? (Assume independent assortment.)

A) 1/8

B) 2/8

C) 4/8

D) 5/8

E) 6/8

Answer: E

5. In the offspring of a dihybrid self, what percentage of the individuals are themselves dihybrid?

A) 6.25%

B) 12.50%

C) 18.75%

D) 25.00%

E) 56.25%

Answer: D

6. A leucine-requiring mutant strain of haploid yeast is crossed to a cysteine-requiring mutant strain. Assuming independent assortment, what proportion of the spores produced will be mutant?

A) 1/16

B) 3/16

C) 1/4

D) 1/2

E) 3/4

Answer: E

7. In a haploid fungus similar to Neurospora, a red-colored mutant is crossed to an alanine-requiring mutant. Assuming independent assortment, what proportion of the spores produced will be alanine-requiring?

A) 1/16

B) 3/16

C) 1/4

D) 1/2

E) 3/4

Answer: D

8. Two pure-breeding mutant plants were crossed: One had small leaves (wild-type leaves are large), and the other made pink flowers (wild-type flowers are purple). All F₁ individuals had small leaves and purple flowers. Assuming independent assortment, what proportion of the F₂ individuals are expected to be phenotypically wild type?

A) 1/16

B) 3/16

C) 1/4

D) 9/16

E) 3/4

Answer: B

9. Mendel’s Y/y; R/r dihybrid pea plants were the F₁ of the cross between a double homozygous dominant and a double homozygous recessive. If we testcrossed these dihybrids, what proportion of the offspring would be recombinant and phenotypically resemble the F₁ dihybrid?

A) 0%

B) 25%

C) 50%

D) 75%

E) 100%

Answer: A

Use the following information to answer questions 10 and 11.

The following is known about the inheritance of size and fur color in Holland lop rabbits:

• Crosses between large individuals only produce large individuals.
• Crosses between dwarf individuals produce both large and dwarf rabbits in a ratio of 1:2. Such crosses also produce some very small kits (baby rabbits) that generally die within a few days.
• Crosses between brown rabbits only produce brown kits.
• Some crosses between black rabbits produce only black kits, whereas others produce both black and brown kits.
• The size and fur-color phenotypes segregate independently.

10.  What are the expected phenotypes in the F₁ of a cross between a dwarf rabbit that breeds true for brown fur color and a large rabbit that breeds true for black fur color?

A) black dwarf only

B) black dwarf and black large only

C) brown dwarf and black dwarf only

D) brown dwarf, brown large, black dwarf, and black large

E) brown large only 

Answer: B

11. A large black doe (female rabbit) gives birth to nine black kits―five are large, and four are dwarf. What are the possible phenotypes of the kits’ father? 

A) black dwarf only

B) black dwarf, brown dwarf, black large, or brown large

C) black dwarf or black large only

D) black dwarf or brown dwarf only

E) black dwarf or brown large only

Answer: D

12. In hogs, a dominant allele B results in a white belt around the body. At a separate locus, the dominant allele S causes fusion of the two parts of the normally cloven hoof resulting in a condition known as syndactyly. A belted syndactylous sow was crossed to an unbelted cloven-hoofed boar, and in the litter there were:

	25% belted syndactylous
	25% belted cloven
	25% unbelted syndactylous
	25% unbelted cloven

The genotypes of the parents can best be represented as which of the following?

 

A) B/B;S/S * b/b;s/s

 B) B/b;S/s * b/b;S/S

 C) B/b;S/s * B/B;s/s

 D) b/b;S/s * B/b;s/s

 E) B/b;S/s * b/b;s/s

Answer: E

13. A female Drosophila with singed bristles is crossed to a male with sepia (dark brown) eyes. In the F₁, all females are wild type, and all males have singed bristles. F₁ males and females are crossed together, and the following F₂ phenotypic ratios are obtained.

	748 wild-type females
	753 wild-type males
	742 singed females
	747 singed males
	249 sepia females
	250 sepia males
	244 singed, sepia females
	246 singed, sepia males

If sn and se represent the mutant alleles of the singed and sepia gene, respectively, and sn⁺ and se⁺ are their wild-type counterparts, what are the most likely genotypes of the original parents?

A) X/X; sn/sn; se⁺/se⁺ and X/Y; sn/sn⁺; se/se

B) X/X; sn/sn; se⁺/se and X/Y; sn/sn⁺; se/se

C) X^sn/X^sn+; se⁺/se⁺ and X^sn+/Y; se/se

D) X^sn/X^sn; se⁺/se⁺ and X^sn+/Y; se/se 

E) X^sn/X^sn; se⁺/se and X^sn+/Y; se/se

Answer: D

14. The pedigree below shows the inheritance patterns of two extremely rare, independent genetic conditions (represented with black and grey symbols, respectively). If individuals A and B have a child, what is the probability that it will have both conditions?

                            

1. A)1/16
2. B)1/9
3. C)1/4
4. D)1/3

Answer: B

15. A pure line of Guinea pigs with genotype A/A; b/b is crossed to a pure line with genotype a/a; B/B. The F₁ male and female Guinea pigs are crossed to each other to generate the F₂. What proportion of the F₂ individuals are the result of a recombinant egg being fertilized by a recombinant sperm?

A) 1/16

B) 2/16

C) 4/16

D) 6/16

E) 10/16

Answer: C

16. If a plant of genotype A/a;B/b;C/c;D/d is selfed and the genes assort independently, how many different genotypes will be found among the progeny?

 A) 4

 B) 16

 C) 24

 D) 64

 E) 81

Answer: A

17. If two mice of genotype F/f;G/g;H/h;I/i;J/j are repeatedly mated, how many different phenotypes will be found in the progeny? (Assume complete dominance for all genes.)

 A) 15

 B) 16

 C) 32

 D) 128

 E) 256

Answer: C

18. In a trihybrid, how many different gamete genotypes can be produced with respect to the three genes of interest? 

 A) 3

 B) 4

 C) 8

 D) 16

 E) 27

Answer: C

19. If an individual has 10 gene pairs, how many different gametes can be formed if 5 of the gene pairs are homozygous and the remaining 5 gene pairs are heterozygous?

A) 20

B) 32

C) 60

D) 64

E) 1024

Answer: B

20. Two pure lines obtained from Mendel’s experiments are crossed to each other. The first line makes green smooth seeds (peas), and the second line has white flowers. All F₁ individuals have purple flowers and produce yellow wrinkled seeds. What proportion of the F₂ plants should have purple flowers and make green wrinkled seeds?

A) 1/64

B) 3/64

C) 1/16

D) 9/64

E) 3/16

Answer: B