In testicular feminization, the testosterone receptor is mutated and individuals can produce testosterone, but cannot initiate the intracellular pathways to respond to the testosterone and therefore develop as females. If a woman is a known carrier for the Tfm mutation, what are the chances that her daughter would have two sons (XY) who were both affected by testicular feminization?

Select one:

a. 1/4

b. 1/64

c. 1/16

d. 1/32

e. 1/2

Heterogametic organisms:

1. produce one type of gamete

2. produce two types of gametes

3. are male in humans

Select one:

a. 1

b. Both 2 and 3

c. 2

d. 3

e. Both 1 and 3

In mammals, dosage compensation for X-linked genes is achieved by:

Select one:

a. decreased heterochromatin structure in the X chromosome in males.

b. hyperactivation of the X chromosome in males.

c. decreased transcription of genes on the female X chromosomes.

d. all of the above

e. inactivating one of the two X chromosomes in females.

In rabbits, the coat color determining gene is an example of multiple alleles. One of these alleles is the wild-type allele. Wild-type alleles are present:

Select one:

a. in half of the individuals in the population

b. in rare situations in the wild population

c. in only wild individuals of the population

d. none of these

e. in most individuals in the population

In rabbit coat color, there are multiple alleles. Wild-type coat color is dominant over all other alleles, and the chinchilla phenotype is seen when two copies of the chinchilla allele are inherited. When you cross a rabbit with chinchilla coat color (cch cch) with a rabbit with Himalayan color (chch) or albino (cc), the offspring of either cross always gives a light gray color. What can be said about the cch allele?

Select one:

a. None of the above

b. the cch allele is codominant with the ch allele

c. the cch allele is incompletely dominant over the ch or c alleles.

d. the ch allele is completely dominant to cch

e. cch is completely dominant to ch

If two individuals have the genotype LMLN, what percentage of their children would you expect to show no reaction with anti-N serum?

Select one:

a. None of the above

b. 3/4

c. 1/2

d. 2/3

e. 1/4

Flies will normally produce red eyes with the wildtype allele. If they do not produce the protein for red eyes, they will have white eyes. If gene expression is completely absent, this is an example of which type of mutation?

Select one:

a. hypermorphic

b. codominant

c. incompletely dominant

d. amorphic or null

e. hypomorphic

Cinnabar-2 and cinnabar are mutations in the same gene. Suppose you set up a cinnabar-2 × cinnabar cross, and you collect the offspring. If you were to breed those offspring with a scarlet mutant, what eye color would you expect in the offspring?

Select one:

a. cinnabar

b. cinnabar-2

c. wild-type

d. white

e. scarlet

Alzheimer’s patients who inherit the mutant allele can exhibit a range of phenotypes, ranging from mild cognitive impairment to severe dementia. This is an example of:

Select one:

a. variable expressivity

b. incomplete penetrance

c. both a and b

d. epistasis

e. sex-influenced expression

Labrador retrievers have two genes controlling coat color. Having a BB or Bb genotype will result in black coat color, while having bb means the dog will be a brown lab. These coat colors can only be expressed if the dog has at least one dominant copy of a second gene, E. If the dog is recessive at that second gene, ee, the dog will be a yellow lab. This is an example of recessive epistasis. If you breed two black labs who are heterozygotes at both genes, what is the expected phenotypic ratio?

Select one:

a. 9 black : 3 brown : 4 yellow

b. 9 brown: 4 black: 3 brown

c. 9 yellow : 4 black : 3 brown

d. 9 black: 3 yellow : 4 brown

e. 9 yellow: 3 brown : 4 black

Suppose you wish to study an inherited disorder, Tay Sachs. In the general population with unrelated parents, the risk of Tay Sachs is approximately 1 in 250. Suppose you have found that among the offspring of first-cousin marriages, the risk of Tay Sachs increases to 16.6 in 250. Thus, the inbreeding coefficient for the first-cousin marriages can be calculated as:

Select one:

a. 1/64

b. 1/32

c. 1/4

d. 1/8

e. 1/16

In a suppression epistasis, one gene produces a pigment, while a second gene produces a suppressor for that protein. Suppose gene A is a pigment, while gene B is a suppressor of that pigment. What is the expected ratio of offspring in a cross between two heterozygotes if the genes exhibit dominant suppression epistasis?

Select one:

a. 9:7

b. 9:3:4

c. None of the above

d. 12:3:1

e. 10:6