AP YAY

A model showing two possible arrangements of chromosomes during meiosis is shown in Figure 1. Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1?

a Does crossing-over generate more genetic diversity than the fusion of gametes does?

b Do mutations prevent independent assortment during metaphase I?

c How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?

d. Do daughter cells that are not genetically identical to parent cells produce viable zygotes?

c How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?

A pea plant with red flowers is test crossed with a homozygous recessive white flowered pea plant, and 3 of the progeny have white flowers and 4 have red. Therefore, the genotype of the red parent was

a. RR

b. Rr

C. rr

d. either RR or Rr.

b. Rr

A blue-flowered African violet of unknown ancestry self-pollinated and produced 50 seeds.

These seeds germinate and grow into flowering plants. Of these plants, 36 produce blue flowers and 14 produce pink flowers. What is the best explanation for the pink-flowered offspring? a.

a. Blue flowers are incompletely dominant to pink flowers.

b. Pink flower color is a trait recessive to blue flower color.

c. Pink flower color is the result of somatic mutations in the flower color gene.

d. A previous generation of the blue-flowered parent must have included 50 percent pink flowered plants.

b. Pink flower color is a trait recessive to blue flower color.

4.-5. In a species of tortoise, foot size (big or small) is controlled by one gene, while shell shape (round or lumpy) is controlled by another gene. Suppose that a big-footed lumpy-shelled tortoise mates with a small-footed round-shelled tortoise. Eight offspring result: four big-footed round-shelled tortoises and four small-footed round-shelled tortoises. (Assume that the parents are not necessarily homozygous for each allele.) bbtr

Which statement about the inheritance of shell shape in tortoises is most likely to be correct, given your genetic analysis of the tortoise family?

1. Lumpy is dominant to round.

2. Round is dominant to lumpy.

3. Round and lumpy are codominant.

4. This cannot be answered without more information.

b Round is dominant to lumpy.

If big feet (B) in tortoises is dominant to small feet (b), what is the genotype of the big-footed parent with respect to the foot gene?

a. bb

b. BB

c. Bb

d. Either bb or BB

c Bb

6. Which statement about an individual that is homozygous for an allele is false?

a. Each of its somatic (body) cells possesses two copies of that allele.

b. Each of its gametes contains one copy of that allele.

c, It is pure-breeding with respect to that allele.

d. Its parents must have been homozygous for that allele.

d. Its parents must have been homozygous for that allele.

7.-8. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed.

7. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. The genotypes of Matthew and Jane are best represented as

a. Matthew: AA Jane: Aa

b.Matthew: Aa Jane: aa

c. Matthew: aa Jane: aa

d. Matthew: aa Jane: Aa

d Matthew: aa Jane: Aa

The probability that Matthew and Jane's first child will be an achondroplastic dwarf is

a. 0%

b. 25%

c. 50%

d. 100%

c. 50%

In labrador retrievers, black color (B) is dominant over chocolate (b). Another locus (E) affects coat pigment deposition. Individuals homozygous recessive (ee) are yellow no matter the genotype at locus B. If a black lab BbEe is crossed with a chocolate lab bbEe, what fraction of offspring will be chocolate?

a. 0/16

b. 4/16

c. 6/16

d. 8/16

c. 6/16

Mendel performed a cross between individuals heterozygous for three different traits: green versus yellow seeds (green is dominant), red versus white flowers (red is dominant), and green versus yellow pods (green is dominant). What fraction of the offspring would have been expected to have green seeds, red flowers, and yellow pods?

a. 27/64

b/ 12/64

c. 9/64

d.6/64

c. 9/64

How many unique gametes are possible from an individual with genotype WWYyZz?

a. 2

b. 4

c. 6

d. 8

b. 4

If your parents were blood type A and O. Which blood type could you possibly be?

a. A and O

b. O only

c. A and B

d. A only

a. A and O

White eyes is a recessive sex-linked trait in fruit flies. If a white-eyed female fruit fly is mated to a red-eyed male, their offspring should be

50 percent red-eyed and 50 percent white-eyed for both sexes.

all white-eyed for both sexes.

all white-eyed males and all red-eyed females.

all white-eyed females and all red-eyed males.

c all white-eyed males and all red-eyed females.

Very few genes have been located on the Y chromosomes of humans. Y-linked genes include a gene called testis-specific protein Y. A male with this gene will

a. pass it to his sons, and sometimes also to his daughters.

b. pass the gene only to his sons.

c. pass the gene only to his daughters.

d. pass the gene to all of his children if the mother is a carrier.

b pass the gene only to his sons.

Which of the following pedigrees are most likely to match sickle cell anemia, a recessive autosomal disorder?

A

B

C

D

a

Both the father and husband of Queen Victoria of England were not affected by the X-linked disease hemophilia, but her son Leopold was affected, as were many of the royal grandsons and great grandsons who were descended from her daughters. The mutation that caused hemophilia in Leopold and other male descendants probably arose as a mutation in

a Queen Victoria

b Victoria's husband, Prince Albert

c Victoria's father

d Victoria's Aunt

a Queen Victoria

Coat color in mice is incompletely dominant. Yellow (Y) and white (W) - colored mice are homozygous, while cream-colored mice are heterozygous (YW). What cross will give 100% cream colored mice?

a Cream x Cream

b White x Cream

c Yellow x Cream

d. White x Yellow

d. White x Yellow

The relative location of four genes on a chromosome can be mapped from the following data on crossover frequencies

Which of the following represents the relative positions of these four genes on the chromosome?

a. ABCD

b. ADCB

c. CABD

d. CBAD

c. CABD

Butterflies of the genus Colias live in the Rocky Mountains, where they experience a wide range of temperatures. Different variants of a particular glycolytic enzyme in the flight muscles are optimally active at different temperatures. Within the same population, some individual butterflies fly most effectively at 29°C, while others fly most effectively at 40°C.

Still others can be equally active at both temperatures. Which of the following claims is most consistent with the observed butterfly behavior?

a Butterflies that express two variants of the enzyme are active over a greater range of temperature.

b.Butterflies that are active over a wide range of temperatures produce greater amounts of the enzyme.

c Temperature has little effect on the activity of butterflies.

d.Butterflies that are active at warmer temperatures produce more offspring.

a Butterflies that express two variants of the enzyme are active over a greater range of temperature.

Red-green color blindness in humans is caused by a recessive allele located on the X chromosome. The figure below shows the potential offspring of a female who is red-green x color-blind and a male with full-color vision. All of the possible male offspring would be color-blind, and all of the possible female offspring would have full-color vision.

If during the production of male gametes an error in meiosis occurred, sperm containing both an X and a Y chromosome could be produced. Individuals with XXY chromosomes have Klinefelter's syndrome and are phenotypically male. How would the extra chromosome affect the male offspring produced by the gamete?

a None of the potential offspring would be male, because the potentially male zygote would have two X chromosomes, and theY chromosome would be ignored.

b The male offspring would all be red-green color-blind, because of interference from alleles on theY chromosome.

c The male offspring would have full-color vision, because of the presence of the extra X chromosome.

d. There would be no change to the phenotypes of the possible offspring, because the extra X chromosome would not be active.

c The male offspring would have full-color vision, because of the presence of the extra X chromosome.