1. A tall pea plant is crossed with a recessive dwarf pea
plant. What will the phenotypic and genotypic ratio of
offspring be
a. if the tall plant was TT?
b. if the tall plant was Tt?
2. A true-breeding tall, purple-flowered pea plant (TTPP)
is crossed with a true-breeding dwarf, white flowered
plant (ttpp).
a. What is the phenotype of the F1 generation?
b. What is the genotype of the F1 generation?
c. What four types of gametes are formed by the F1
plants?
d. Create and solve a punnett square to show the
offspring of the F2 generation.
d. List the phenotypes and ratios found in the F2
generation.
3. In the following cross, what is the probability of
obtaining offspring that show all three dominant
traits, A_B_C_ ( _ indicates that the second allele
can be either dominant or recessive without
affecting the phenotype determined by the first
dominant allele)?
AaBbcc x AabbCC
a. probability of offspring that are A_B_C_ = ?
b. What is the probability that the offspring of
this AaBbcc x AabbCC cross will show at least two
dominant traits?
5. A dominant allele M is necessary for the production
of the black pigment melanin, mm individuals are
white. A dominant allele B results in the deposition
of the a lot of pigment in an animal’s hair, producing
a black color. The genotype bb produces brown hair.
Two black animals heterozygous for both genes are
bred. Using MmBb x MmBb:
a. List the three phenotypes and possible
genotypes
b. List the ratios for each of the three
phenotypes.
Phenotype
Genotype
Ratio
Linked Genes
Given: b + = gray
b = black
vg += normal wings
vg = vestigial wings
Cross: (Male) b+ b vg + vg X (Female) b b vg vg
1. Mendel’s law of independent assortment
would produce which phenotypes?
2. The actual results pg.280
6. Determine the sequence of genes along a
chromosome based on the following
recombination frequencies:
A-B, 8 map units
A-C, 28 map units
A-D, 25 map units
B-C, 20 map units
B-D, 33 map units
7. A man with hemophilia (a recessive, sex linked
condition) has a daughter of normal phenotype.
She marries a man who is normal for the trait.
a. What is the probability that a daughter of this
mating will be a hemophiliac?
b. That a son will be hemophiliac?
c. If the couple has four sons, what is the
probability that all four will be born with
hemophilia?
8. Red-green colorblindness is caused by a SL
recessive allele. A CB man marries a woman with
normal vision whose father was CB. What is the
probability of having a daughter who is also CB?
What is the probability that their first son will be
CB?
9. A wild-type fruit fly (heterozygous for gray body
color and normal wings) is mated with a black fly
with vestigial wings. The offspring have the
following phenotypic distribution: wild type 778,
black vestigial 785, black normal 158, gray vestigial
162. What is the recombination frequency
between these genes for body color and wing size?