Unit IV | Mutation

1. Mutation
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CO1.1
Noida Institute of Engineering and Technology
(Pharmacy Institute) Greater Noida
Abhijit Debnath
Asst. Professor
NIET, Pharmacy
Institute
Unit: 4
Subject Name: Biotechnology
(BP605T)
Course Details
(B. Pharm 6th Sem)

2. Mutation
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 Mutation
 Types of Mutation
 Diseases Caused By Mutation
 The Causes of Mutations
 Mutants Arise by Mutation
CO1.1
Noida Institute of Engineering and Technology
(Pharmacy Institute) Greater Noida

3. A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division,
exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. Germ line mutations occur
in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed
on.
MUTATION CO4.2
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4.  Mutations can also occur as the result of exposure to environmental factors such as smoking, sunlight and radiation.
 Often cells can recognise any potentially mutation-causing damage and repair it before it becomes a fixed mutation.
 Mutations can also be inherited, particularly if they have a positive effect.
 For example, the disorder sickle cell anaemia is caused by a mutation in the gene that instructs the building of a
protein called haemoglobin. This causes the red blood cells to become an abnormal, rigid, sickle shape. However, in
African populations, having this mutation also protects against malaria.
 However, mutation can also disrupt normal gene activity and cause diseases, like cancer
 Cancer is the most common human genetic disease; it is caused by mutations occurring in a number of growth-
controlling genes. Sometimes faulty, cancer-causing genes can exist from birth, increasing a person’s chance of getting
cancer.
MUTATION CO4.2
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5. MUTATION CO4.2
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6. TYPES OF MUTATION CO4.2
P – Point mutation, or any insertion/deletion entirely inside one gene
D – Deletion of a gene or genes
C – Whole chromosome extra, missing, or both
T – Trinucleotide repeat disorders: gene is extended in length

7. TYPES OF MUTATION CO4.2

8. TYPES OF MUTATION CO4.2

9. • Sickle cell disease is a group of disorders that
affects hemoglobin, the molecule in red blood
cells that delivers oxygen to cells throughout the
body.
• People with this disease have atypical
hemoglobin molecules called hemoglobin S,
which can distort red blood cells into a sickle, or
crescent, shape.
SICKLE CELL ANEMIA CO4.2
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10. SICKLE CELL ANEMIA CO4.2
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11. SICKLE CELL ANEMIA CO4.2
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12. • Also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome
21.
• It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual
disability.
• The average IQ of a young adult with Down syndrome is 50, equivalent to the mental age of an 8 or 9 year old child,
but this varies widely.
DOWN SYNDROME CO4.2
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13. • Chromosomal disorder caused by the presence of all or part of an extra 18th chromosome.
• This genetic condition almost always results from nondisjunction during meiosis.
• After John Hilton Edwards, who first described the syndrome in 1960.
EDWARD’S SYNDROME CO4.2
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14. • Monosomy 7 is typically characterized by early- childhood onset of evidence of
bonemarrow insufficiency/failure associated with increased risk for myelodysplastic
syndrome (MDS) or acute myelogenous leukaemia (AML).
MONOSOMY 7 CO4.2
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15. THE CAUSES OF MUTATIONS CO4.2
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Four classes of mutations are
(1) spontaneous mutations (molecular decay),
(2) mutations due to error-prone replication bypass of naturally occurring DNA damage (also called error-
prone translesion synthesis),
(3) errors introduced during DNA repair, and
(4) induced mutations caused by mutagens.

16. THE CAUSES OF MUTATIONS CO4.2
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 Scientists may also deliberately introduce mutant sequences through DNA manipulation for the sake of scientific
experimentation.
 One 2017 study claimed that 66% of cancer-causing mutations are random, 29% are due to the environment (the
studied population spanned 69 countries), and 5% are inherited.
 Humans on average pass 60 new mutations to their children but fathers pass more mutations depending on their
age with every year adding two new mutations to a child.

17. MUTANT CO4.2
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 A mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally
an alteration of the DNA sequence of the genome or chromosome of an organism.
 It is a characteristic that would not be observed naturally in a specimen.
 The term mutant is also applied to a virus with an alteration in its nucleotide sequence whose genome’s in the nuclear
genome.
 The natural occurrence of genetic mutations is integral to the process of evolution.
 Although not all mutations have a noticeable phenotypic effect, the common usage of the word "mutant" is generally a
pejorative term, only used for genetically or phenotypically noticeable mutations.
 Previously, people used the word "sport" (related to spurt) to refer to abnormal specimens. The scientific usage is
broader, referring to any organism differing from the wild type.

18. MUTANTS ARISE BY MUTATION CO4.2
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 Mutants arise by mutations occurring in pre-existing genomes as a result of errors of DNA replication or errors of DNA
repair.
 Errors of replication often involve translesion synthesis by a DNA polymerase when it encounters and bypasses a
damaged base in the template strand.
 A DNA damage is an abnormal chemical structure in DNA, such as a strand break or an oxidized base, whereas a
mutation, by contrast, is a change in the sequence of standard base pairs.
 Errors of repair occur when repair processes inaccurately replace a damaged DNA sequence. The DNA repair process
microhomology-mediated end joining is particularly error-prone.