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
Labrador retrievers are black, brown, or yellow. In a cross of a
black female with a brown male,
results can be either all black
puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow
puppies.
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
In one type cross of black × black, the results were as
follows:
9/16 black
4/16 yellow
3/16 brown
The
genotype eebb must result in which of the following?
A)
black
B) brown
C) yellow
D) a lethal result
E) white
yellow
Radish flowers may be red, purple, or white. A cross between a
red-flowered plant and a white-
flowered plant yields all-purple
offspring. The part of the radish we eat may be oval or long,
with
long being the dominant trait.
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
8) 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
Drosophila (fruit flies) usually have long wings (+), but mutations
in two different genes can
result in bent wings (bt) or vestigial
wings (vg).
If a homozygous bent wing fly is mated with a homozygous vestigial
wing fly, which of the
following offspring would you
expect?
A) all +bt +vg heterozygotes
B) 1/2 bent and 1/2
vestigial flies
C) all homozygous + flies
D) 3/4 bent to 1/4
vestigial ratio
E) 1/2 bent and vestigial to 1/2 normal
all +bt +vg heterozygotes
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
Tallness (T) in snapdragons is dominant to dwarfness (t), and red (R)
flower color is dominant to
white (r). The heterozygous condition
results in pink (Rr) flower color.
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