Genetics Exam 2 Practice Questions
Samples of old exam questions
1. Two pure-breeding mutant plants produce white flowers. When they are crossed, all of the progeny have wild-type purple flowers. What does this genetic complementation test tell you?
a. The genes are part of distinct biosynthetic pathways
b. The two lines exhibit different mutations in the same gene
c. More than one gene is involved in determining the phenotype
d. The allele is pleiotropic
e. The allele exhibits incomplete dominance
2. In a testcross of two plants where one parent is tall and has normal leaves and the other parent is a dwarf and has mottled leaves (tm/tm), the following numbers of progeny genotypes are counted.
Genotype
#Observed
TM/tm
101 tm/tm 97
Tm/tm
8 tM/tm 7
What configuration is the first parent in?
a. Repulsion: TM/tm
b. Repulsion: Tm/tM
c. Coupling: TM/tm
d. Coupling: Tm/tM
e. Not enough information is given to determine this.
3. In a species of beetle, a heterozygous female with a blue shell, long antennae and brown eyes is mated with a male that is homozygous recessive for all traits (green shell: b, short antenna: a, black eyes: e).
The following progeny (1000 total) were observed.
PHENOTYPES
NUMBER OBSERVED wild 321 green shell
38
black eyes
130
short antenna
18
green shell, short antenna, black eyes
309
short antenna, black eyes
32
green shell, short antenna
140
green shell, black eyes
12
What is the correct gene map for these genes?
a. b---10mu---a-------30mu-------e
b. a---10mu---b------30mu-------e
c. a-------30mu------e---10mu---b
d. a----7mu----b------27mu------e
e. b----7mu----a------27mu------e
4. How many distinct phenotypes exist for a trait determined by three additive genes?
a. Three
b. Five
c. Seven
d. Six
e. Nine
5. A series of experiments shows that oil content in a diploid grain is influenced by five genes (a through
e) with additive alleles. The highest producing strain is 20% oil content; the lowest has close to 0%. A
plant
1. Two pure-breeding mutant plants produce white flowers. When they are crossed, all of the progeny have wild-type purple flowers. What does this genetic complementation test tell you?
a. The genes are part of distinct biosynthetic pathways
b. The two lines exhibit different mutations in the same gene
c. More than one gene is involved in determining the phenotype
d. The allele is pleiotropic
e. The allele exhibits incomplete dominance
2. In a testcross of two plants where one parent is tall and has normal leaves and the other parent is a dwarf and has mottled leaves (tm/tm), the following numbers of progeny genotypes are counted.
Genotype
#Observed
TM/tm
101 tm/tm 97
Tm/tm
8 tM/tm 7
What configuration is the first parent in?
a. Repulsion: TM/tm
b. Repulsion: Tm/tM
c. Coupling: TM/tm
d. Coupling: Tm/tM
e. Not enough information is given to determine this.
3. In a species of beetle, a heterozygous female with a blue shell, long antennae and brown eyes is mated with a male that is homozygous recessive for all traits (green shell: b, short antenna: a, black eyes: e).
The following progeny (1000 total) were observed.
PHENOTYPES
NUMBER OBSERVED wild 321 green shell
38
black eyes
130
short antenna
18
green shell, short antenna, black eyes
309
short antenna, black eyes
32
green shell, short antenna
140
green shell, black eyes
12
What is the correct gene map for these genes?
a. b---10mu---a-------30mu-------e
b. a---10mu---b------30mu-------e
c. a-------30mu------e---10mu---b
d. a----7mu----b------27mu------e
e. b----7mu----a------27mu------e
4. How many distinct phenotypes exist for a trait determined by three additive genes?
a. Three
b. Five
c. Seven
d. Six
e. Nine
5. A series of experiments shows that oil content in a diploid grain is influenced by five genes (a through
e) with additive alleles. The highest producing strain is 20% oil content; the lowest has close to 0%. A
plant