REVIEW PAPER ON MUTAGEN
LEE, MAKA
08301016024
ABSTRACT
A mutagen is a sauce of a mutation. There are physical mutagen and chemical mutagen, and
both categories include great variations. As the variation of mutagen, the conduct of each type
of mutagen is different. When a mutation is occurred by mutagen, there are also many
different possibilities might happen in our bodies.
INTRODUCTION
From this review, we are going to see the definition of mutagen, the variation of mutagen. We
are also going to see how a mutation occurs and what will happen after a mutation. We are
also going to looking for some happening about the mutagen and mutation in our dairy life in
a more practical view. For the definition of the mutagen, we see the definition from the literal
view and also from its properties and characteristics. For the variation, we look for the
variation in different categories in their nature. For each kind of mutagen we will see how the
mutagen works and how it causes mutation in our bodies. We will look at how our bodies
react to the mutation. In the end we will see some facts about the mutation in our bodies.
THE DEFINITION OF MUTAGEN
A mutagen is an agent that can change the genetic information of a living organism which
these changes are called mutation. [1] Inside the bodies of an organism, there are a lot of
spontaneous mutation is occurred, and these spontaneous mutation might also affected by
environment. [2] So, in overall respects, a mutagen is a factor that can increase the mutation
rate in living organism. Mutagens are usually chemical compounds or ionizing radiation,
electromagnetic radiation. The effects of some mutagens are increased or suppressed in some
organisms by the presence of certain other, nonmutagenic substances, oxygen, for example,
makes cells more sensitive to the mutagenic effects of X-rays. [3]
THE VARIATION OF MUTAGEN
Mutagens are mainly classified into two categories. One is physical mutagen, and the other
one is chemical mutagen. Physical mutagen includes ionizing radiation like X-ray, gamma ray,
and alpha particles or nonionizing radiation like ultraviolet radiation. [4] In another respect,
because the spontaneous mutation rate of an organism is somehow affected by heat, so heat
can also considered as one type of physical mutagen. For the chemical mutagen category,
there are a lot of chemical compounds are considered as mutagen. For example, base analogs,
bromine and some compounds that contain bromine in their chemical structure, sodium azide,
psoralen, benzene, alkaloid plants, transposon, deaminating agents such as nitrous acid,
intercalating agents such as ethidium bromide, alkylating agents such as ethylnitrosourea,
etc.[5] For different categories, the basic mechanism of mutation also varies a lot.
THE CONDUCTS AND EFFECTS OF MUTAGEN
When an organism is exposed to a mutagen, it’s not necessary that mutation occurs. Mutagen
may give a chance for mutation in an organism. When an organism is exposed to a physical
mutagen, like ionizing radiation, due to the strong energy of the radiation, the molecule
changes in genetic material might happen. This kind of change is called molecular lesion. It’s
known that there are 100~1,000,000 molecular lesions occurred in a human body per day. [6]
If the molecular lesion is occurred in DNA, that is called a mutation. The molecular lesion
might cause the mutation as well. When the molecular lesion occurs, the enzyme in the cells
will recognize the lesion, and repair the lesion by a mechanism called DNA repair. If the cell
is disable to repair the DNA damage, the cell might became an irreversible state of dormancy,
known as senescence, or perform cell suicide, also known as apoptosis or programmed cell
death, or might cause mutation in the cell.[7] The chemical mutagen disturbs the DNA
replication and causes the changes in DNA information. Mutation rates in higher eukaryotes
are roughly 0.1–100 per genome per sexual generation but are currently indistinguishable
from 1/300 per cell division per effective genome. [8] When the cell is mutated, there are many
cases for the cell. Major probability of the mutation effects are just silent, it means there will
be no effect, since there are a lot of introns in human gene. Sometimes, the mutation will
cause the difference in surviving abilities of the cell. When these kinds of changes occur, in
worst case, the cancer or tumor might be occurred.
LITERATURE CITED
1.
http://science.jrank.org/pages/4529/Mutagen.htm
2.
http://www.microbiologyprocedure.com/gene-mutation/spontaneous-mutations.htm
3.
http://www.britannica.com/EBchecked/topic/399695/mutation
4.
Brusick, David. Principles of Genetic Toxicology, 2nd ed. New York: Plenum Press, 1987.
5.
http://en.wikipedia.org/wiki/Mutagen
6.
Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J.
(2004). Molecular Biology of the Cell, p963. WH Freeman: New York, NY. 5th ed.
7.
http://en.wikipedia.org/wiki/DNA_repair#cite_note-lodish-0
8.
John W. Drake, Brian Charlesworth, Deborah Charlesworth, and James F. Crow. Rate of
spontaneous mutation. Genetics, Vol. 148, 1667-1686, April 1998, Copyright © 1998