In each generation of this family after generation I, the age at diagnosis is significantly lower
than would be found in nonfamilial (sporadic) cases of this cancer (~63 years). What is the most
likely reason?
A) Members of this family know to be checked for colon cancer early in life.
B) Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial
forms.
C) This is pure chance; it would not be expected if you were to look at a different family.
D) This cancer requires mutations in more than this one gene.
E) Affected members of this family are born with colon cancer, and it can be detected whenever
they are first tested.

Hereditary (or familial) cases of this cancer typically occur at earlier ages than do nonfamilial
forms.

What is the probability that individual III-1 is Ww?
A) 3/4
B) 1/4
C) 2/4
D) 2/3
E) 1

1

What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

50%

What is the probability that individual III-1 is Ww?
A) 3/4
B) 1/4
C) 2/4
D) 2/3
E) 1

1

From this pedigree, how does this trait seem to be inherited?
A) from mothers
B) as an autosomal recessive
C) as a result of epistasis
D) as an autosomal dominant
E) as an incomplete dominant

as an autosomal dominant

The affected woman in generation IV is thinking about her future and asks her oncologist
(cancer specialist) whether she can know whether any or all of her children will have a high risk
of the same cancer. The doctor would be expected to advise which of the following?
I. genetic counseling
II. prenatal diagnosis when/if she becomes pregnant
III. testing to see whether she has the allele
IV. testing to see whether her future spouse or partner has the allele
A) I only
B) II only
C) I, II, and IV only
D) I, II, and III only
E) III and IV only

I, II, and IV only

If 1,000 F2 offspring resulted from the cross, approximately how many of them would you
expect to have red, terminal flowers?
A) 65
B) 190
C) 250
D) 565
E) 750

190

Among the F2 offspring, what is the probability of plants with white axial flowers?
A) 9/16
B) 1/16
C) 3/16
D) 1/8
E) 1/4

3/16

These results indicate which of the following?
A) Brown is dominant to black.
B) Black is dominant to brown and to yellow.
C) Yellow is dominant to black.
D) There is incomplete dominance.
E) Epistasis is involved.

Epistasis is involved.

How many genes must be responsible for these coat colors in Labrador retrievers?
A) 1
B) 2
C) 3
D) 4
E) 5

2

The genotype eebb must result in which of the following?
A) black
B) brown
C) yellow
D) a lethal result
E) white

yellow

If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1
will be expected to be which of the following?
A) red and long
B) red and oval
C) white and long
D) purple and long
E) purple and oval

purple and long

In the F2 generation of the above cross, which of the following phenotypic ratios would be
expected?
A) 9:3:3:1
B) 9:4:3
C) 1:1:1:1
D) 1:1:1:1:1:1
E) 6:3:3:2:1:1

6:3:3:2:1:1

The flower color trait in radishes is an example of which of the following?
A) a multiple allelic system
B) sex linkage
C) codominance
D) incomplete dominance
E) epistasis

incomplete dominance

If flies that are heterozygous for both the bent wing gene and the vestigial wing gene are
mated, what is the probability of offspring with bent wings only?
A) 1/8
B) 3/8
C) 1/4
D) 9/16
E) 3/16

3/16

A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers.
What are the genotype and phenotype of the F1 individuals?
A) ttRr–dwarf and pink
B) ttrr–dwarf and white
C) TtRr–tall and red
D) TtRr–tall and pink
E) TTRR–tall and red

TtRr–tall and pink

If snapdragons are heterozygous for height as well as for flower color, a mating between
them will result in what ratio?
A) 9:3:3:1
B) 6:3:3:2:1:1
C) 1:2:1
D) 27:9:9:9:3:3:3:1
E) 9:4:3

6:3:3:2:1:1

How many different types of gametes would be possible in this system?
A) 1
B) 2
C) 4
D) 8
E) 16

4

One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If
each allele confers a unit of color darkness such that S1 has one unit, S2 has two units, and so on,
then what proportion of their offspring would be expected to have five units of color?
A) 1/4
B) 1/5
C) 1/8
D) 1/2
E) 0

1/2

The relationship between genes S and N is an example of
A) incomplete dominance.
B) epistasis.
C) complete dominance.
D) pleiotropy.
E) codominance.

epistasis.

A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce
A) all sharp-spined progeny.
B) 50% sharp-spined, 50% dull-spined progeny.
C) 25% sharp-spined, 50% dull-spined, 25% spineless progeny.
D) all spineless progeny.
E) It is impossible to determine the phenotypes of the progeny.

all sharp-spined progeny.

If doubly heterozygous SsNn cactuses were allowed to self-pollinate, the F2 would segregate
in which of the following ratios?
A) 3 sharp-spined:1 spineless
B) 1 sharp-spined:2 dull-spined:1 spineless
C) 1 sharp-spined:1 dull-spined:1 spineless
D) 1 sharp-spined:1 dull-spined
E) 9 sharp-spined:3 dull-spined:4 spineless

9 sharp-spined:3 dull-spined:4 spineless

A blue budgie is crossed with a white budgie. Which of the following results is not possible?
A) green offspring only
B) yellow offspring only
C) blue offspring only
D) green and yellow offspring
E) a 9:3:3:1 ratio

green and yellow offspring

Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were
white. What are the most likely genotypes for the two blue budgies?
A) yyBB and yyBB
B) yyBB and yyBb
C) yyBb and yyBb
D) yyBB and yybb
E) yyBb and yybb

yyBb and yyBb

Which of the following is a possible partial genotype for the son?
A) IBIB
B) IBIA
C) ii
D) IBi
E) IAIA

IBi

Which of the following is a possible genotype for the mother?
A) IAIA
B) IBIB
C) ii
D) IAi
E) IAIB

IAi

Which of the following is a possible phenotype for the father?
A) A negative
B) O negative
C) B positive
D) AB negative
E) impossible to determine

B positive

If both children are of blood type M, which of the following is possible?
A) Each parent is either M or MN.
B) Each parent must be type M.
C) Both children are heterozygous for this gene.
D) Neither parent can have the N allele.
E) The MN blood group is recessive to the ABO blood group.

Each parent is either M or MN.

One species of a small birdlike animal has an extremely variable tail length, an example of
polygenic inheritance. Geneticists have come to realize that there are eight separate genes for tail
length per haploid genome, with each gene having two alleles. One allele for each gene (a1, b1,
and so on) increases the length by 1 cm, whereas the other allele (a2, b2, and so on) increases it
by 0.5 cm. One bird was analyzed and found to have the following genotype:
a1a1b2b2c1c2d1d2e2e2f1f2g1g1h1h2
What is the length of its tail?
A) 6 cm
B) 8 cm
C) 12 cm
D) 24 cm
E) 36 cm

12 cm

One species of green plant, with frondlike leaves, a spine-coated stem, and purple cup-
shaped flowers, is found to be self-pollinating. Which of the following is true of this species?
A) The species must be haploid.
B) Its reproduction is asexual.
C) All members of the species have the same genotype.
D) Some of the seeds would have true-breeding traits.
E) All of its dominant traits are most frequent.

Some of the seeds would have true-breeding traits.

If the environmental parameters, such as temperature, humidity, atmosphere, sunlight, and so
on, are mostly Earthlike, which of the following do you expect of its types of leaves, stems, and
flowers?
A) The genes for them would have originated on Earth.
B) Genes for these traits would have a common ancestor with those from Earth.
C) Such plants could be safely eaten by humans.
D) Genotypes for these traits would be identical to those of Earth plants with the same traits.
E) Phenotypes would be selected for or against by these environmental factors.

Phenotypes would be selected for or against by these environmental factors.