Mutagenesis is the process by which genetic information of an organism is changed in a stable manner, resulting in a mutation. It can occur naturally or through exposure to mutagens, and can be achieved experimentally using laboratory procedures. The document discusses the history of mutagenesis research and different types of mutagenesis techniques like directed, site-directed, PCR, insertional, and transposon mutagenesis. It also describes an experiment studying the effects of plant hormones like ABA and auxin on root growth in maize mutants with mutations in rop genes. The results found some rop mutants had slower root growth in response to certain hormones, supporting the hypotheses, while others showed no effect.

2. Mutagenesis
It is a process by which the genetic information of
an organism is changed in a stable manner, resulting in
a mutation.
It may occur spontaneously in nature, or as a result of
exposure to mutagens.
It can also be achieved experimentally using
laboratory procedures

3. DNA may be modified, either naturally or artificially, by a number
of physical, chemical and biological agents, resulting in mutations
In 1927, Hermann Muller first demonstrated that mutation
with observable changes in the chromosomes can be caused
by irradiating fruit flies with X-ray.
HISTORY :
Lewis Stadler also showed the mutational effect of X-ray on
barley in 1928, and ultraviolet (UV) radiation on maize in 1936.

4. Types of mutagenesis
1. Directed mutagenesis
Directed mutagenesis can be done using :
Directed mutagenesis may define is a change in the nucleic acid
sequence (or genetic material) of an organism at a specific
predetermine Site. directed mutagenesis is incorporation of a
desired amino acid (of one's choice) in place of a specific amino acid
in a protein or a polypeptide.
Site-directed mutagenesis is the technique for generating amino
acid coding changes in the DNA (gene). By this approach specific
(site-directed) change (mutagenesis) can be made in the base (or
bases) of the gene to produce a desired enzyme.

5. 2. Site-directed mutagenesis
• In molecular biology and genetics, mutations are
changes in a genomic sequence.
• Mutations are caused by radiation, viruses, transposes and
mutagenic chemicals, as well as errors that occur during
meiosis or DNA replication.
• Site-directed mutagenesis, also called site-specific
mutagenesis or oligonucleotide directed mutagenesis, is a
molecular biology technique often used in bio molecular
engineering in which a mutation is created at a defined site
in a DNA molecule.

6. 3. PCR mutagenesis
4. Insertional mutagenesis
5. Signature tagged mutagenesis
6. Transposon mutagenesis

7. Role of plant Harmon in
mutagenesis
 The experiments are designed to measure the
effects of
- Abscisic acid (ABA)
- Auxin
 Samples are
-Wild-types
- mutated at rop genes

8. Maize rop mutants
 There are nine rop genes in maize
 used samples with mutation of the rop 2, rop
6 and rop 7 genes.
 How do you get the mutation?

9. Experiment set up
 Germinate seedlings in a water soaked paper
towel
 Measure root length
before treatment
 Add auxin or ABA
 Measure after 24 and 48hrs
 Average the length

10. Auxin – rop 6/7
Day Two Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowh
Wildtype grow th
Mutant grow th
Day One Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wildtype grow th
Mutant grow th
Mutant Effect !!
rop 6/7 Double
mutant
SLOWER root
growth

11. Auxin rop 2
Day One Compaison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wildtype grow th
Mutant grow th
Day Two comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wildtype growth
Mutant growth
No Mutant Effect !!!
rop 2 mutant
SAME as wild-type

12. ABA rop 2
Day One Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wildtype grow th
Mutant grow th
Day Two Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wildtype grow th
Mutant grow th
Mutant Effect !!
rop 2 mutant
SLOWER root growth

13. ABA- rop 6/7
Day One Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%ofrootgrowth
Wild-type growth
Mutant growth
Day Two Comparison
0
20
40
60
80
100
120
0 1 2 3 4
%rootgrowth
Wild-type grow th
Mutant grow th
No Mutant Effect !!!
rop 6/7 mutant
SAME as wild-type

14. Summary of Results
 ABA,Auxin
 Auxin rop 6/7 Supports hypothesis
Auxin rop 2 No effect
 ABA rop 2 Supports hypothesis
 ABA rop 6/7 No effect
Root growth
Rop

15. Hormonal Factors of Mutagenesis and
Anti-Mutagenesis Regulation.
Case study 1
Mekhtizadeh Emin RZA
292 92
The genetic activity of phytohormones (Phs) was studied. The investigation was
conducted with 4 plants (Allium fistulosum, Lycopersicon esculentum,
Triticum aestivum, and Gossypium hirsutum). The action of Phs on plant genetic
processes was evaluated by chromosome aberration testing. It was observed that
the exogenic Phs exerted a stabilizing effect on spontaneous plant mutagenesis.
The use of Phs before and after the action of mutagenic factors contributed to an
increase in the anti-mutational or reparative function of the plants´ genes.
It was observed that the Phs exhibited gene protective or reparative activity.
The absence of clearly expressed dependence of these effects on Ph dose was
recorded.
Turkish Journal of Biology 2009Vol. 33 No. 1 pp. 15-20
Conclusion :

16. Beale, G. (1993). "The Discovery of Mustard Gas Mutagenesis by
Auerbach and Robson
in 1941". Genetics 134 (2): 393–399.
Crow, J. F.; Abrahamson, S. (1997). "SeventyYears Ago: Mutation
Becomes Experimental". Genetics 147 (4): 1491–1496
https://en.wikipedia.org/wiki/Mutagenesis
http://www.cabdirect.org/search.htm
dergipark.ulakbim.gov.tr/tbtkbiology/article/view
Reference :