BIOL/PBIO 3333
Genetics
Quiz 2
2/20/15
For answers to the quiz, click here:
1. In Indian pea fowl, the wild-type plumage is glossy metallic blue. Cameo plumage, which produces brown feathers, results from a Z-linked allele that is recessive to the glossy blue wild type allele. If a blue female were crossed to a cameo male, what results would be expected in the progeny? a) all blue males and females; b) all brown males and females; c) blue males and cameo females; d) cameo males and blue females; e) 3:1 ratio of blue:brown, regardless of sex.
2. There are three types of plumage found in mallard ducks, determined by three alleles at a single locus: M
R
, restricted; M , mallard, and m d
, dusky. The dominance relationships between these alleles is M R >M > m d . Which of the following crosses would be expected to produce a progeny plumage ratio of 2:1:1? a) M
R
M x m d m d
; b) M
R m d x M
R
M; c) M
R m d x Mm d
; d) M
R
M x Mm d
; none of the above.
For question 3, please use the following code:
For questions 1-3, please use the following code: a) All of the statements are correct. b) I, II, and III are correct. c) I and III are correct. d) II and IV are correct. e) only IV is correct.
3. A geneticist crosses two yellow mice with straight hair and obtains the following progeny: ½ yellow, straight; 1/6 yellow, fuzzy; ¼ agouti, straight; 1/12 agouti, fuzzy.
This cross indicates:
I) that these two genes are linked;
II) that the fuzzy hair phenotype is recessive to straight;
III) that an agouti mouse strain can never breed true;
IV) that these progeny are the product of a dihybrid cross.
4. In some sheep, the presence of horns is produced by an autosomal allele that is dominant in males and recessive in females. A horned female is crossed with a hornless male. One of the resulting F
1
females is now crossed with a hornless male. What proportion of the male and female progeny of this cross will have horns? a) all males, all females; b) all males; ½ females; c) ½ males, ½ females; d) ½ males, no females; e) no males; no females.
Questions 5-6 pertain to the following: In dragons, the recessive genes for rectangular scales ( and sulfurous breath ( b r) , bat-like wings (
) are all recessive to the wild type alleles for oval scales, eagle wings and fiery breath. A female heterozygous for all three genes were mated to a b ) phenotype
+ r s b r +
+ + +
+ r + b r s
+ + s b + s b + + number of progeny
42
2
19
189
13
1
204
30

male homozygous recessive for all traits. The phenotypes of the recovered progeny are given in the table on the right:
5. The distance, in map units, between the r and s loci is: a) 7 m.u. b) 11 m.u. ; c) 15 m.u.; d) 22 m.u.; e) these genes are not linked.
6. The interference value for this experiment is: a) 0.006; b) 0.07; c) 0.43; d) 0.57; e) 1.75.
Questions 7-8 pertain to the following three point testcross data, where a trihybrid pipeweed plant is testcrossed, following the segregation of three recessive traits, loose leaf
( l ), green stem ( g ), and turbid smoke ( t ).
7. The map distance between the l and g loci is: a) 3.8 map units; b) 7.6 map units; c) 16.6 map units; d) 41.8 map units; e) the two genes show no evidence of linkage.
8. The map distance between the t and g loci is: a) 3.8 map units; b) 7.6 map units; c) 16.6 map units; d) 41.8 map units; e) the two genes show no evidence of linkage.
Questions 9 and 10 pertain to the following. Neurospora fungi of genotype ab were crossed to a mating type that contained the wild type alleles for these two gene loci. In the chart below, 100 individuals are scored for spore genotype distribution:
1 2 3
Tetrad Classes
4 5 6 7 a b a b a b a b
+ +
+ +
+ +
+ +
30 a b a b a + a +
+ b
+ b
+ +
+ +
8 a b a b
+ b
+ b
+ +
+ + a + a +
5 a + a + a + a +
+ b
+ b
+ b
+ b
30 a + a + a b a b
+ b
+ b
+ +
+ +
10
+ b
+ b a b a b a + a +
+ +
+ +
7
+ b
+ b
+ +
+ + a b a b a + a +
8
8 a + a +
+ b
+ b a b a b
+ +
+ +
2
9. The distance between the a gene and the centromere is approximately: a) 1 map unit b) 2 map units; c) 7 map units; d) 15 map units; e) none of the above.
10. The distance between the a and b genes is approximately: a) 7 map units; b) 14 map units; c) 21 map units; d) 50 map units; e) the a and b genes are not linked.