Download Types of mutation

Name: Ibrahim Munirat.
Matric no: 14/sci05/006.
Department: microbiology.
College: science.
Genetics assignment: Mutation a curse or a blessing.
The action or process of mutating:"the mutation of punk's angry energy into something more
thuggish and mindless” synonyms: alteration, change, variation, modification, transformation,
metamorphosis, transmutation, transfiguration, sea change, evolution humorous
transmogrification "cells that have undergone mutation".
The changing of the structure of a gene, resulting in a variant form which may be transmitted to
subsequent generations, caused by the alteration of single base units in DNA, or the deletion,
insertion, or rearrangement of larger sections of genes or chromosomes ’’ mutation is,
ultimately, the only way in which new variation enters the species".
Classes of mutation
1 Point mutation: this is often caused by chemicals or malfunction of DNA replication, exchange
of a single nucleoticide for another which are classified as transitions.
2 chromosomal abbreviations.
Types of mutation
There are many different ways that DNA can be changed, resulting in different types of
mutation.
—Silent mutation: this code for the same or sufficiently similar amino acids.
—Missense mutations: This code for a different amino acid, such mutation is responsible for
disease such as sickle cell disease, epidermolysis bullosa.
—Nonsense mutation: this code for a premature stop codon which results in truncated
nonfunctional protein products.
—Substitution:
Substitution is a mutation that exchanges one base for another (i.e., a change in a single
"chemical letter" such as switching an A to a G). Such a substitution could:
1 change a codon to one that encodes a different amino acid and cause a small change in the
protein produced. For example, sickle cell anemia is caused by a substitution in the betahemoglobin gene, which alters a single amino acid in the protein produced.
2 change a codon to one that encodes the same amino acid and causes no change in the
protein produced. These are called silent mutations.
3 change an amino-acid-coding codon to a single "stop" codon and cause an incomplete
protein. This can have serious effects since the incomplete protein probably won't function.
—Insertions:
Insertions are mutations in which extra base pairs are inserted into a new place in the DNA.
—Deletions
Deletions are mutations in which a section of DNA is lost, or deleted.
—frameshifts:
Since protein-coding DNA is divided into codons three bases long, insertions and deletions can
alter a gene so that its message is no longer correctly parsed. These changes are called
frameshifts.For example, consider the sentence, "The fat cat sat." Each word represents a
codon. If we delete the first letter and parse the sentence in the same way, it doesn't make
sense. In frameshifts, a similar error occurs at the DNA level, causing the codons to be parsed.
Other types are misdivision of centromere, translocation, inversion.
Advantages of mutation in science and medicine
1 survival:
Mutations have allowed humans to adapt to their environment. For instance, lactose tolerance
is a specific external mutation that was advantageous in societies that raised cows and goats.
Mutations have been responsible for antibiotic resistance in bacteria, sickle cell resistance to
malaria, and immunity to HIV, among others. A rare gene mutation leading to unusual
shortness of height has proven to be advantageous for a particular Ecuadorian community.
National Public Radio's (NPR) Jon Hamilton writes how the Ecuadorian community with the rare
gene mutation known as Laron syndrome is protected against cancer and diabetes.
2 Diversity:
In 2008, Professor Eiberg from the Department of Cellular and Molecular Biology stated,
“Originally, we all had brown eyes but a genetic mutation affecting the OCA2 gene in our
chromosomes resulted in the creation of a 'switch,' which literally 'turned off' the ability to
produce brown eyes.” He explains that things like “hair color, baldness, freckles, and beauty
spots” are all brought about by mutations.
Disadvantages of mutation in medicine
1 disease:
As much as mutations have helped humans, mutations are also the cause of certain diseases.
For instance, in 2008 in one of the science news it was explained on how a particular mutation
relatively common on the Indian subcontinent predisposes people to heart disease. Many other
diseases, such as cancer, diabetes and asthma, are linked to genetic mutations.
2 Genetic disorder:
A genetic disorder is a disease that is caused by an abnormality in an individual's DNA.
Abnormalities can range from a small mutation in a single gene to the addition or subtraction of
an entire chromosome or set of chromosomes.” Non-disjunction is one of the most common
types of mutations. Down syndrome is a non-disjunction and a common genetic disorder that
has other consequences such as developmental delays.
Mutation is a natural process that changes a DNA sequence. And it is more common than you
may think. Mutation are dividing, a "typo" occurs every 100,000 or so.
Mutations have allowed humans to adapt to their environment. For instance, lactose tolerance
is a specific external mutation that was advantageous in societies that raised cows and goats.
Mutations have been responsible for antibiotic resistance in bacteria, sickle cell resistance to
malaria, and immunity to HIV, among others. A rare gene mutation leading to unusual
shortness of height has proven to be advantageous for a particular Ecuadorian community.
National Public Radio's (NPR) Jon Hamilton writes how the Ecuadorian community.
People commonly use the terms "mutant" and mutation" to describe something undesirable or
broken. But mutation is not always bad. Most DNA changes fall in the large areas of the
genome that sit between genes, and usually they have no effect. When variations occur within
genes, there is more often a consequence, but even then mutation only rarely causes death or
disease. Mutation also generates new variations that can give an individual a survival
advantage. And most often, mutation gives rise to variations that are neither good nor bad, just
different base substitution.
Mutation Generates New alleles
The whole human family is one species with the same genes. Mutation creates slightly different
versions of the same genes, called alleles. These small differences in DNA sequence make every
individual unique. They account for the variation we see in human hair color, skin color, height,
shape, behavior, and susceptibility to disease. Individuals in other species vary too, in both
physical appearance and behavior.
Genetic variation is useful because it helps populations change over time. Variations that help
an organism survive and reproduce are passed on to the next generation. Variations that hinder
survival and reproduction are eliminated from the population. This process of natural selection
can lead to significant changes in the appearance, behavior, or physiology of individuals in a
population, in just a few generations.
Once new alleles arise, meiosis and sexual reproduction combine different alleles in new ways
to increase genetic variation.
A mutation is a permanent change in the sequence of DNA. In order for an observable
effect, mutations must occur in gene exons or regulatory elements. Changes in the non-coding
regions of DNA (introns and junk DNA) generally do not affect function.
Causes of mutation
Mutations can be caused by external (exogenous) or endogenous (native) factors, or they
may be caused by errors in the cellular machinery. Physical or chemical agents that induce
mutations in DNA are called mutagens and are said to be mutagenic.
— Exogenous factors: environmental factors such as sunlight, radiation, and smoking can
cause mutations.
–Endogenous factors: errors during DNA replication can lead to genetic changes as can toxic
by-products of cellular metabolism.
Consequences of mutation
Mutations can be advantageous and lead to an evolutionary advantage of a certain
genotype. Mutations can also be deleterious, causing disease, developmental delays, structural
abnormalities, or other effects.
Mutation is a long term blessing and a short term curse.
Almost all mutations are either neutral or bad. "Bad" meaning they decrease the health and/or
survivability prospects of the recipient of said mutation. Generally, if a mutation is noticeable,
it would be what we refer to as a "birth defect" or a "genetic disease."
Very occasionally, there is a "good" mutation, that gives a survivability advantage to its
recipient, whether that advantage be an adaptation to its environment (most common) or an
actual increase in the sophistication of the organism (very, very rare). Evolution depends on
these, and life would have never progressed beyond some sort of simple self-catalyzing
chemical reaction if not for these positive mutations. But positive mutations ,even those of the
adaptive nature -- are extremely rare compared to flat-out bad mutations.
Remember that evolution is a cruel process of trial and (mostly) error, and it took billions of
years to get us where we are today.
So, it's great that mutations have allowed us to evolve to what we are. But you'd probably like
for your child to have as few mutations as possible, because the chances of a mutation being in
any way positive one are pretty much negligible. On the other hand, the likelihood of that
mutation being a birth defect are, sadly, not at all negligible.