Zoo/Bot 3333
Genetics
Quiz 2
10/3/08
For the answers to the quiz, please click here:
1. In radishes, color and shape are each controlled by a single locus with two
incompletely dominant genes that segregate independently. Color may be red (RR),
purple (Rr) or white (rr) and shape may be long (LL) oval (Ll) or round (ll). If two plants
heterozygous for both loci are crossed, what fraction of the progeny would be expected to
be purple and long?
a) 1/16; b) 1/8; c) 3/16; d) 3/8; e) none of the above.
Questions 2-3 pertain to the following. A yellow male canary is crossed to a green
female. When the F1 progeny are scored, all the males are green and all the females are
yellow.
2. Which of the following are consistent with the above data?
a) two different autosomal gene loci are involved; b) the green locus is epistatic to the
yellow gene locus; c) yellow color is dominant in males and recessive in females; d) two
of the above are true; e) none of the above.
3. A cross between two of the F1 siblings will produce in the F2:
a) equal numbers of green and yellow females; b) equal numbers of green and yellow
males; c) certain males that can only produce yellow females; d) all of the above; e) none
of the above.
Questions 4-5 pertain to the following. In rabbits, agouti (wild-type) coat color (c+) is
dominant over chinchilla (cch), which is dominant over Himalayan (ch) which is dominant
over albino (c).
4. How many different genotypes can be derived from this multiple allelic series?
a) 4; b) 8; c) 10; d) 16; e) 64.
5. What is the phenotypic ratio expected from the cross c+ch x cchc?
a) 1 agouti: 1 chinchilla; b) 3 agouti: 1 chinchilla; c) 2 agouti: 1 chinchilla : albino;
d) 1 agouti: 1 chinchilla : 1 himalayan: 1 albino; e) none of the above.
6. A mutation in the myocilin gene:
a) causes a form of X-linked muscular dystrophy; b) is associated with a form of juvenile
glaucoma; c) is associated with early death due to aortic aneurysm; d) shows complete
penetrance; e) more than one of the above is true.
Questions 7-8 pertain to the following: In Tribbles, the genes for blue body (b), yellow
hair (y) and purple eye color (p) are all recessive to the wild type alleles. Females
heterozygous for all three genes were mated to males homozygous recessive for all traits.
The phenotypes of the recovered progeny are given in
the table on the right:
Phenotype Progeny Recovered
4
byp
7. The distance, in map units, between the yellow and
93
by+
purple loci is:
54
b+p
a) 6.5 ; b) 10; c) 13; d) 20; e) greater than 30.
349
b++
331
8. The coefficient of coincidence for this experiment
+yp
is:
66
+y+
a) 0.026; b) 0.25; c) 0.385; d) 0.75; e) none of the
97
++p
above.
6
+++
Total
1000
A cross is carried out between two strains of Neurospora, one carrying a mutation,
designated a, which confers a requirement for a particular amino acid, and the other
carrying a mutation, termed g, which results in abnormal growth. An examination of 437
asci indicates that seven classes are formed in the following frequencies:
Classes
1 and 2
Spore pairs 3 and 4
5 and 6
7 and 8
total
1
ag
++
ag
++
1
2
a+
++
ag
+g
37
3
ag
ag
++
++
2
4
ag
++
a+
+g
3
5
a+
+g
a+
+g
3
6
a+
a+
+g
+g
316
7
ag
a+
++
+g
75
9. The gene order for these loci is:
a) a-----g-----centromere; b) g-------a-------centromere; c) a-----centromere-------g; d) the
genes are not linked in this cross; e) can not be determined from the information given.
10. The approximate distance from the centromere to gene a is:
a) 5 map units; b) 10 map units; c) 15 map units; d) 20 map units; e) 36 map units.