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

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S,
have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time,
a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn
cactuses have no spines at all.

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

Feather color in budgies is determined by two different genes, Y and B, one for pigment on the
outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is
blue; YYbb or Yybb is yellow; and yybb is white.

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

A woman who has blood type A positive has a daughter who is type O positive and a son who is
type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is
designated by the alleles R and r, respectively. A third gene for the MN blood group has
codominant alleles M and N.

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.

Humanoids on the newly explored planet Brin (in a hypothetical galaxy in ~50 years from the
present) have a gene structure similar to our own, but many very different plants and animals.

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

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?

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.