1 BSCI411, Plant Genetics & Molecular Biology Midterm exam ...

BSCI411, Plant Genetics & Molecular Biology
Midterm exam, March 15, 2001
Your Name:________________________ SS#_________________________
1. You are provided with EMS-mutagenized M2 seeds of Arabidopsis. Briefly describe
how you are going to screen for mutants defective in leucine biosynthesis?
2. If you have obtained five such mutants (a1 to a5), how are you going to determine
whether they are recessive or dominant (describe the genetic crosses)?
3. If all five mutants are recessive, you then performed complementation tests to test if
they are allelic (mutation in the same gene) or not allelic. You have obtained
following results from such complementation tests (+: wild-type phenotype in F1,
-: mutant in F1). How many complementation groups are there? How are these five
mutations grouped into different complementation groups?
a1 a2 a3 a4 a5
a1 - + + + -
a2 - - + +
a3 - + +
a4 - +
a5 -
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4. A scientist is studying flower pigment synthesis in petunia. These flowers are usually
dark purple. She has obtained several mutants defective in the pigment biosynthesis
pathway. These mutants are: c1: white flower, p1: red flower; p2; pink flower. She
then tested the epistatic relationship among these mutants by constructing double
mutants. Her results: c1 p1: white, c1 p2: white, p1 p2: pink. Indicate which gene
(C1, P1 or P2) acts first in the pigment biosynthesis pathway, which acts second and
which acts last.
5. Based on the ABC model, describe the floral organ type in each whorl:
Whorls: 1 2 3 4
WT Sepal Petal Stamen Carpel
a mutant:
b muatnt:
c mutant:
bc double mutants:
c mutants carrying a 35S-B transgene:
6. Dr. Franks has mapped a gene named SEUSS to chromosome I of Arabidopsis. He
then try to determine the distance between SEUSS and a chromosome I marker CZ1:
CZ1
SEUSS
seuss was originated in the Ler ecotype and was crossed into a Wild-type plant (Col
ecotype). The F1 progeny of this cross is wild-type in phenotype but is heterozygous for
seuss in genotype. He let the F1 plant self and then isolated DNA from 13 seuss mutant
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plants in F2. CZ1 primers were used to PCR-amplify the CZ1 locus from 13 individual
seuss mutants. The PCR fragment was then diggested with EcoR1 and then run on a 1%
agarose gel. The following is the image from the gel after electrophoreses:
Ler Col 1 2 3 4 5 6 7 8 9 10 11 12 13
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a. What type of a marker is CZ1? (RFLP? SSLP? CAPS? SNPs?).
b. What is the distance (in % recombination) between SEUSS and CZ1 ? Show your
work.
7. Following is a sequencing gel. What is the DNA sequence? Label 5’ and 3’.
ddA ddG ddC ddT (added to each sequencing reaction)
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8. Indicate differences between following terms. Try to indicate as many difference as
you can (even include advantages/disadvantages, application ect.)
Genomic DNA library vs. cDNA library
Microarray vs. DNA chip
Cis-regulatory elements vs. Trans-acting factors
CAPS vs. RFLP
Promoter vs Enhancer
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