Zoo Bot 3333
Genetics
Quiz 2
2/27/09
For answers to the quiz, click here:
1. Considering the ABO blood types in humans, identify the genotypes that would be expected for the two
parents depicted below:
Female parent: Blood type A: father type B
Male parent: Blood type A: mother type O
What blood types would be possible among the offspring of this couple?
a) type A; b) type AB; c) type O; d) all of the above; e) only two of the above are correct.
Questions 2-3 pertains to the following. In the guinea pig, one locus involved in the control of coat color
may be occupied by any of four alleles: C (full color); ck (sepia); cd (cream); or ca (albino). The order of
dominance is C > ck > cd > ca.
2. A sepia guinea pig was crossed to cream guinea pig. The sepia guinea pig had an albino parent and the
cream guinea pig had two sepia parents. What would be the phenotypes and the ratios of the progeny
produced in this cross?
a) 1 sepia: 1 cream; b) 3 sepia: 1 cream; c) 1 sepia: 2 cream: 1 albino; d) 3 cream: 1 albino; e) none of the
above.
3. A sepia guinea pig was crossed to a cream guinea pig. The sepia guinea pig had two full color parents
and the cream guinea pig had two sepia parents. What would be the phenotypes and the ratios of the
progeny produced in this cross?
a) 1 sepia: 1 cream; b) 3 sepia: 1 cream; c) 1 sepia: 2 cream: 1 albino; d) 3 cream: 1 albino; e) none of the
above.
4. Horses can be cremello (a light cream color) chestnut (a brownish color) or palomino (a golden color
with white in the tail). Of these phenotypes, only palominos never breed true. The following phenotypes
and ratios were observed in several crosses:
Cremello x palomino
1 cremello: 1 palomino
Chestnut x palomino
1 chestnut: 1 palomino
Palomino x palomino
1 chestnut: 2 palomino: 1 cremello
These results are most consistent with:
a) three different alleles at a single gene locus; b) incomplete dominance; c) recessive epistasis; d)
complementary gene action; e) none of the above.
5. In a species in the cat family, eye color can be gray, blue, green or brown, and each trait is truebreeding. In separate crosses involving homozygous parents, the following were observed:
Cross
1
2
3
P1
Green x gray
Green x brown
Gray x brown
F1
All green
All green
All green
F2
3 green: 1 gray
3 green: 1 brown
9 green: 3 brown: 3
gray: 1 blue
In a cross between a gray-eyed cat and one of unknown genotype, the F1 generation was not observed.
However, the F2 resulted in the same F2 ratio as cross 3. The genotypes of the original parents (P1
generation) can be represented as:
a) AA x aa; b) AAbb x AABB; c) AAbb x aaBB; d) AA′ x Aa; e) AaBb x AaBb.
Questions 6-8 pertain to the following. In corn, a threepoint testcross is conducted to follow the
transmission of the recessive alleles: bm (brown midrib), v, (virescent seedling) and pr (purple aleurone).
The results of the cross are as follows:
Phenotype
Number of Progeny
virescent
200
purple
237
brown
82
virescent, brown
230
virescent, purple
79
purple, brown
195
wild type
42
virescent, purple, brown
44
6. Which locus appears to be in the middle?
a) pr; b) v; c) bm; d) all three genes assort independently; e) two of the genes are linked and the third is on
another chromosome.
7. The distance between the bm and pr gene loci is:
a) 7.8 map units; b) 35.6 map units; c) 42.1 map units; d) 22.3 map units; e) none of the above.
8. The interference value for the above cross is:
a) .097; b) 0.196; c) 0.63; d) 0.80; e) none of the above.
Questions 9 and 10 pertain to the following. Neurospora fungi of genotype a+ were crossed to a mating
type that contained the mutant +b alleles for these two gene loci. In the chart below, 1000 individuals are
scored for spore genotype distribution:
Spore
number
1
2
3
4
5
6
7
8
totals
-------------------------------------------------Ascus Types-------------------------------------------
1
2
3
4
5
6
7
++
++
ab
ab
+b
+b
a+
a+
5
++
++
ab
ab
++
++
ab
ab
1
+b
+b
ab
ab
++
++
a+
a+
5
a+
a+
a+
a+
+b
+b
+b
+b
808
+b
+b
a+
a+
+b
+b
a+
a+
90
++
++
++
++
ab
ab
ab
ab
1
++
++
+b
+b
a+
a+
ab
ab
90
9. The distance between the a gene and the centromere is approximately:
a) 5.05 map units; b) 10.1 map units; c) 9.3 map units; d) 19.2 map units; e) none of the above.
10. The distance between the a and b genes is approximately:
a) 1.2 map units; b) 5.2 map units; c) 10.25 map units; d) 20.5 map units; e) the a and b genes are not
linked.