Download what is mutation?

NAME: KAREEM OMOBOLANLE
DEPARTMENT: HUMAN NUTRITION DIETETICS
MATRIC NO: 14/MHS02/033
COURSE: GENETICS BIO 201
IS MUTATION A CURSE OR A BLESSING?
WHAT IS MUTATION?
Mutation is the changing of the structure of a gene, resulting in a variant form
which may be transmitted to subsequence the generations, caused by the
alternation of single base units in DNA, or the deletion, insertion, or
rearrangement of larger sections of genes or chromosomes. Most commonly, a
single base substituted for another. Sometimes a base is deleted or an extra
based added. Fortunately, the cell is able to repair most of these changes.
When a DNA change remains unrepaired in a cell that will become an egg or a
sperm, it is passed down to offspring.
TYPES OF MUTATION
DELETION: genetic material is removed or deleted. A few bases can be deleted
or it can be complete or partial loss of a chromosome
FRAMESHIFT: the insertion or deletion of a number of bases that is not a
multiple of 3. This alters the reading frame of the gene and frequently results
in a premature stop codon and protein truncation
INSERTION: when genetic material is put into another region of DNA. This may
be the insertion of 1 or more bases, or it can be part of one chromosome being
inserted into another, non-homologous chromosome
MISSENSE: a change in DNA sequence that changes the codon to be different
amino acid. Not all missense mutations are deleterious, some changes can
have no effect. Because of the ambiguity of missense mutations, it is often
difficult to interpret the consequences of these mutations in causing disease
NONSENSE: a change in the genetic code that results in the coding for a stop
codon rather than an amino acid. The shortened protein is generally nonfunction or its function is impeded
WHAT CAUSES 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.
ADVANTAGES OF MUTATION
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 has been responsible for antibiotic resistance to malaria, and
immunity to HIV, among other. A rare gene mutation leading to unusual
shortness of height has proven to be advantageous.
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
explain further that things like “hair color, baldness, freckles and beauty spots”
are all brought about by mutations.
DISADVANTAGES OF MUTATION
DISEASES: as much as mutations have helped humans, mutations are also the
cause of certain diseases. For instance, E! Science news 2008 explains how a
particular mutation relatively common on the Indian subcontinent predisposes
people to heart disease. Many other diseases, such diabetes and asthma are
linked to genetic mutations
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 additional or subtraction of an entire
chromosome or set of chromosomes. Non-disjunction is one of the most
common types of mutations. Down syndrome is non-disjunction and a
common genetic disorder that has other consequences such as developmental
delays.