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Life Science Research and Sustainable Development ISBN: 978-98-84663-33-9

Table.2: Chemical mutagens
Mutagen Example Mode of action
group
Alkylating 1-methyl-1-nitrosourea (MNU); React with bases and add methyl or ethyl
agents 1-ethyl-1-nitrosourea (ENU); groups and, depending on the affected atom,
methyl methane sulphonate the alkylated base may then degrade to yield
(MMS); ethyl methane an abasic site, which is mutagenic and
sulphonate (EMS); dimethyl recombinogenic, or mispair to result in
sulphate (DMS); diethyl mutations upon DNA replication.
sulphate (DES).
Azide Sodium azide Same as alkylating agents.
Hydroxylam Hydroxylamine Same as alkylating agents.
ine
Antibiotics Actinomycin D; mitomycin C; Chromosomal aberrations also reported to
azaserine; streptonigrin cause cytoplasmic male sterility.
Nitrous acid Nitrous acid Acts through deamination, the replacement
of cytosine by uracil, which can pair with
adenine and thus through subsequent cycles
of replication lead to transitions.
Acridines Acridine orange Intercalate between DNA bases thereby
causing a distortion of the DNA double helix
and the DNA polymerase in turn recognizes
this stretch as an additional base and inserts
an extra base opposite this stretched
(intercalated) molecule. This results in frame
shifts, i.e. an alteration of the reading frame.
Base 5-bromouracil (5-BU); maleic Incorporate into DNA in place of the normal
analogues hydrazide; 5- bases during DNA replication thereby
bromodeoxyuridine; 2- causing transitions (purine to purine or
aminopurine (2AP) pyrimidine to pyrimidine); and
tautomerization (existing in two forms
which interconvert into each other, e.g.
guanine can exist in keto or enol forms).

Discussion
In mutation breeding, concept of induced mutation for the improvement of crop fore run to the
beginning of 20th century. During the past 89 years, for the crop improvement through mutation
breeding plays a crucial role and also support the pace made using traditional methods of plant
breeding (Amin et al., 2015). Due to emergence of induced mutation which plays a vital role in
the development of crop varieties with desirable features all over the world, cultivation of
different crop varieties has continued to be successful over the past five decades.
The plant breeding programs due to use of induced mutants across all over the world has
led to official release of 3,362 mutant plant varieties from 240 different plant species in more than
75 countries throughout the world (FAO/IAEA, 2020). Varieties developed by mutation breeding
increase the biodiversity due to presence of variation among them which serves as a baseline for

https://jesjalna.org/Zoology-Publications/index.html 3 Department of Zoology, J. E. S. College, Jalna