Definition of Mutation – Mutation is a change in the genetic material of a cell that is
passed on to its offspring. Mutations can be caused by errors in the replication of genetic
material during cell division caused by radiation, chemicals (mutagens), viruses, or can occur during the
process of meiosis. Check out a more complete explanation of the following mutations,
Sinaumed’s:
A. Definition of Mutation
Mutations are changes that occur in genetic material both at the gene level and at the chromosomal level.
The purpose of mutation is to deal with natural changes that will arise at any time, so that when changes occur,
there are two possibilities that can arise, namely the mutated trait is more adaptable than the original trait,
so that the original character may disappear from circulation.
Another possibility is that the mutated trait is not suitable for the new environment, so that the
individual or population of a species that has it will decrease or become extinct. Based on
this, it can be said that whether or not the mutated individual is suitable or not depends on the area where
the individual or population lives.
Mutations themselves are divided into Big Mutations and Small Mutations, Small Mutations only cause small changes
that are sometimes not obvious in the phenotype or in other words there are variations where the mutated
individual is only slightly different from their parents.
Conversely, large mutations cause obvious changes in the phenotype and cause the phenotype of the offspring
to be abnormal. Major mutations are the basis for a heritable source of variation in living
organisms. Learn about mutations in the book Quantification and Phylogenetics of DNA
Mutations.
B. Causes of Mutations
Mutations are events that change the information contained in DNA. Changes in this information
can occur on a small scale in a few nucleotide bases, or on a chromosomal scale involving millions of
nucleotide bases.
Mutations can cause both good and bad changes and produce genetic variations. Mutations can be
caused by internal and external factors. Mutations in DNA can cause changes in the resulting
protein. Changes to the resulting protein can make a difference in humans.
Several diseases in humans caused by mutations are color blindness and thalassemia. There are
several types of mutations including substitution, deletion, insertion, duplication, inversion,
translocation and others.
The factors that cause mutations come from many aspects of environmental factors. These
factors are known as mutagens. In general, environmental factors that cause mutations
(mutation) are divided into:
1. Physical Factors (Radiation)
Mutagenic agents from physical factors in the form of radiation. Mutagenic radiation, among
others, comes from cosmic rays, ultraviolet rays, gamma rays, X-rays, beta particles, heavy ion emission
neutrons, and other rays that have ionizing power.
Radiation is emitted by materials that are radioactive. A radioactive substance can change
spontaneously into another substance that gives off radiation. There are radiations that cause
ionization, there are those that don’t.
Radiation that causes ionization can penetrate materials, including living tissue, through cells and ionize
the molecules of substances in cells, so that these substances do not function normally or even become
damaged. Visible rays of radio waves and heat from the sun or fire, also form radiation, but
are not destructive.
2. Chemical Factors
Chemical Mutagens, for example colchicine and digitonin substances. Colchicine is a substance
that can inhibit the formation of spindle fibers in the anaphase process and can inhibit cell division
during anaphase. Other substances, for example:
- Pesticides: DDT (agricultural and household insecticides), DDVP (insecticide, fumigam, livestock
helminthic), Aziridine (used in the textile, wood and paper industries to kill house flies, mutagen in
wasps, mice, neurospora, E, coli, and bacteriophage T4), TEM (used in textiles and medicine, eradicates
house flies, mutagens in mice and insects, fungi, aberrations in mice, allium e coli and leukocytes). - Food and beverages: Caffeine (found in many drinks, coffee, tea, chocolate and lemonade containing cola, in
the medical field for antihistamines and drugs for dizziness, blood vessel expansion, coronary), cyclamate
and cyclohexylamine (widely used for flavoring food and beverages , Sodium nitrite and nitric acid (these
substances are used to preserve meat, fish and cheese).
3. Biological Factors
More than 20 kinds of viruses cause chromosomal damage, for example the hepatitis virus causes aberrations
in the blood and bone marrow. Measles, yellow fever, and smallpox viruses can also cause
aberrations.
C. Types of Mutations
Mutations at the gene level are called point mutations, while mutations at the chromosomal level are
usually called aberrations. Mutations in genes can lead to the emergence of new alleles and
form the basis for new variations within species. Mutations occur at a low frequency in nature,
typically lower than 1:10,000 individuals. Other types of mutations, including:
1. Point mutation
Point mutations are changes to the N base of DNA or RNA. Point mutations are common but their
effects can be mitigated by gene recovery mechanisms.
Point mutations can result in changes in the sequence of amino acids in proteins and changes or loss of
enzyme function. Currently, many technologies use point mutations as markers (also called SNPs)
to study changes that occur in genes and are associated with phenotypic changes.
An example of a gene mutation is the reaction of nitric acid with adenine to form hypoxanthine.
This substance will then take the place of the original adenine and pair with cytosine instead of
thymine. Gene mutations are divided into three types, namely silent mutations, non-sense
mutations, and miss-sense mutations.
Silent mutations or silent mutations are codon changes that do not change the amino acid. This
means that changes in DNA nucleotide bases have no effect on protein structure.
In the figure, the AA nucleotide pairs change to TU, but the amino acids remain. A non-sense
mutation is a meaningless mutation in which the mutation changes the amino acid codon to a stop codon.
The stop codon stops the production of amino acids in the ribosome, so protein cannot be
produced.
Miss-sense mutations are mutations that change the codons of nucleotide bases and cause their amino acids
to change. However, most proteins resulting from missense mutations are still functionally
usable. Frame mutations or frameshift mutations are insertions or deletions of nucleotide
bases. From the figure it can be seen that the T and A bases are removed from the DNA chain
thereby changing the amino acids and making the mutated protein unusable.
2. Big Mutation
Chromosomal mutations, often also called major mutations or chromosomal aberrations, are changes in the
number of chromosomes and the arrangement or sequence of genes in the chromosomes. Chromosomal
mutations often occur due to errors in meiosis and few in mitosis.
3. Aneuploidy
Aneuploidy is a change in the number of n which indicates the number of sets of chromosomes.
For example, human body cells have 2 packages of chromosomes so they are called 2n, where one human
n package has 23 chromosomes. Aneuploidy is divided into two, namely autopolyploidy and
allopolyploidy. In autopolyploidy, the n doubles due to errors in meiosis, while in
allopolyploidy, namely marriage or hybridization between species with different number of sets of
chromosomes.
4. Aneusomy
Aneusomy is a change in the number of chromosomes. The cause is anaphase lag (the event of
spindle threads not attaching to the centromere) and non disjunction (failure to separate).
Aneusomy in humans can cause:
- Klinefelter’s syndrome, karyotype (22 AA+XXY), Trisomic condition of the gonosome chromosomes.
Sufferers of Klinefelter’s Syndrome are male, but their testicles do not develop (testicular
dysgenesis) so that they have aspermia and cannot have children (gynaecomastis). - Jacobs syndrome, karyotype (22AA+XYY), Trisomic condition of the gonosome chromosomes.
People with this syndrome generally have psychopathic psychological disorders.
Research itself shows that most of the people who go to prison are people who suffer from
Jacobs Syndrome. - Turner syndrome, with a karyotype (22AA+X0, a condition in which the number of chromosomes is 45 and one sex
chromosome is missing. The patient with Turner Syndrome is female, but the ovum does not develop (ovaricular
dysgenesis). - Patau syndrome, karyotype (45A+XX/XY), Trisomic condition on autosomal chromosomes. This
autosome has an abnormality on chromosome number 13, 14, or 15. - Edward’s syndrome, karyotype (45A+XX/XY), Trisomic condition on autosomes. Autosomes have
abnormalities on chromosome number 16,17, or 18. Patients with this syndrome have an oval skull, short
broad shoulders, slightly downturned ears and abnormal
5. Chromosomal Mutations
Chromosomal mutations are mutations that cause changes in genetic material on a large scale.
According to bbc.co.uk, there are four types of chromosomal mutations, namely deletions,
translocations, inversions and duplications.
Deletion Deletion is the loss of part of a chromosome during meiosis. If the chromosome is
broken or the telomere is damaged, the chromosome will lose many of the genes that are important for the
expression of the individual.
Deletion can lead to death of the individual in the form of a zygote or death at an early age.
In addition to deletions, there are also insertions where chromosomes experience additional pieces
of chromosomes.
- Deletion Deletion is the loss of part of a chromosome during meiosis. If the chromosome
is broken or the telomere is damaged, the chromosome will lose many of the genes that are important for
the expression of the individual. Deletion can lead to death of the individual in the form
of a zygote or death at an early age. In addition to deletions, there are also insertions
where chromosomes experience additional pieces of chromosomes. - Translocation Reporting from ThugtCo, translocation is a mutation caused by the attachment of a piece
of chromosome to a non-homologous chromosome. Translocations can cause unexpressed genes to
become a serious problem. - Inversion is the event of attaching the broken chromosome back to the original chromosome, but with
the reverse position. Inversions are called silent mutations because they do not cause
serious problems in the individual. - Duplication is a chromosomal mutation in which some chromosomes replicate causing the addition of the same
gene in one section.
D. Benefits and Disadvantages of Mutations
Mutations are changes that occur in the genetic material, both DNA and RNA. These changes can
occur at the level of the gene sequence (also called point mutations) or at the level of the chromosome
sequence which is called aberration. The probability of a mutation occurring in nature is as
much as 1 in 10,000 individuals.
1. Mutation Benefits
In general, mutations are harmful, the mutants are lethal and homozygous recessive. However,
mutations can also be beneficial, among other things, through mutations, superior polyploid plants can be
created. For example, seedless watermelons, seedless oranges, large strawberries, and so on.
Mutation is also one of the keys to evolution in the world.
We can see this in the evolution that has occurred in humans from time to time which is discussed in the book The
Britannica Education Series: Evolution which is packaged with various illustrations so that learning is fun.
The formation of polyploid plants is beneficial for humans, but detrimental for plants that have mutations,
because these plants become unable to reproduce generatively. Although biologically most
mutations cause disturbances in individual conditions, mutations are actually one of the keys to adapting a
species (species) to a new or ever-changing environment. This positive side is exploited by a
number of fields of applied biology, including:
a. Tumor Therapy
The application of radiotherapy radiation (such as irradiation with X-rays) and chemotherapy is useful in
inhibiting the development of tumor cells and cancer. This therapy functions to induce
mutations in cancer cells. The mutation agent will cause the target cells to stop growing
because they are unable to reproduce themselves.
b. Breeding
Exposure of plants to ionizing radiation, such as gamma rays from Co-60, or to certain chemicals, such as
EMS and DS. In this application, mutations are not intended to kill the cell, but to change the
arrangement of nitrogenous bases in the DNA or to cause segmental mutations. The hope is that
some cells will develop beneficial mutations. These mutations are mostly carried out on
horticultural crops, such as vegetables and ornamental plants.
c. Improved Crop Yield
Seedless fruits, such as watermelons, are produced. If we are going to cultivate watermelons,
it is necessary to pay attention to its production. Watermelon fruit will have a better selling
value if it is large and without seeds.
For that it is necessary to administer colchicine. Colchicine can be purchased at herbal
medicine stores. How to use colchicine can be read on the label instructions for use in plants.
Through the implementation of this mutation, it can provide good business opportunities in
increasing the yields of the crops we plant, so as to increase income.
Through mutation events, ornamental plants that have high economic value can be obtained, for example, what
is popular in society today is the Aglonema ornamental plant. The price of this plant reaches
tens of millions of rupiah. This can be used as a promising business opportunity.
This new variety can be produced by giving colchicine to plants.
Mutations can increase agricultural production, including wheat, tomatoes, polyploid coconuts, polyploid
cabbage, and so on. The yield of antibiotics, such as Penicillium mutants, will increase even
more. Mutation is a very useful process for evolution and genetic variation.
One example we can see in various plant cultivation techniques in the book Basics of Plant Cultivation
Techniques.
2. Negative Impact of Mutations
Besides having several benefits, mutations also have negative impacts, you know . The
negative effects of mutations include impacts on humans, namely the emergence of diseases such as Turner
Syndrome, Klinefelter, Jacob Syndrome, Patau Syndrome, Edward Syndrome, Metafemale, and Sickle Cell
Anemia. The following is a more detailed explanation:
- Turner syndrome is a genetic disorder in women due to a lack of one X chromosome. Usually, women have
XX sex chromosomes, totaling 46 pieces, but in people with Turner Syndrome, the chromosomes become XO
and only have 45 pieces. People with Turner Syndrome are also infertile. - Jacob’s syndrome affects men. Jacob’s syndrome occurs because there is 1 extra Y
chromosome in males, so the chromosome becomes XYY. Although it causes genetic disorders,
this syndrome is not hereditary. - Klinefelter’s syndrome is a disorder caused by an extra X chromosome in males. Therefore,
in Klinefelter’s sufferers, the chromosome becomes XXY. One of the visible physical
characteristics of sufferers of this syndrome is enlarged breasts. Apart from Klinefelter’s
syndrome, another disorder caused by imperfect gene mutations is Patau’s syndrome - Patau Syndrome or Trisomy 13. People with Patau Syndrome have 3 copies of chromosomes and have an
abnormality on the 13th chromosome. In addition, Patau’s syndrome is a genetic condition,
so this disease can only be inherited by lineage. - Edward’s syndrome is also a chromosomal disorder. The chromosome that has abnormalities
in Edward’s Syndrome is chromosome number 18. One of the characteristics of babies who have Edward’s
Syndrome is the fingers that overlap with the condition of the palms of the hands clasping.
The next syndrome caused by chromosomal abnormalities is metafemale syndrome - Metafemale Syndrome This syndrome is often also called the superwoman syndrome, which causes the
sufferer to have a larger stature than women in general. This is due to the extra X
chromosome in the sufferer, so that people with Metafemale Syndrome usually have XXX chromosomes.
Source: from various sources
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