This document discusses mutations, which are heritable changes in an organism's genome. Mutations can occur spontaneously during DNA replication due to errors, or can be induced by mutagens like UV radiation or chemicals. Mutations provide genetic variation and are the raw material for evolution, though they are generally harmful. They can result in the formation of new alleles and allow organisms to evolve and adapt to their environments. The document covers different types of mutations and their molecular basis.

1. MUTATION
Submitted by: Karishma Shaw
M.Sc 1st year, Semester 2.
Department of biochemistry and molecular
biology.
Reg no. – 17368015.
Submitted to : Dr. K . Jeevaratnam.
Department of biochemistry and molecular
biology.

2. INTRODUCTION.
 WHAT IS MUTATION?
 Genome is not a static entity. It is subject to
different typesof heritable changes.
 A sudden and heritable change in the sequence
of an organism’s genome that gives rise to
alternate forms of any gene is called mutation.
 It does not result from recombination.

3.  The process by which mutations are produced is
called mutagenesis.
 An organism exhibiting a novel phenotype as a result
of presence of mutation is referred to as a mutant.
General characteristics of mutation:
 Generally recessive, but dominant mutations also
occur.
 Generally harmful to organisms.
 Are random,occur at anytime and in any cell of an
organism.
 Are recurrent.

4. ROLE OF MUTATION.
 Ultimate source of all genetic variation and it
provides raw materials for evolution.
 Results in formation of alleles.
 Organisms are able to evolve and adapt.

5. MOLECULAR BASIS OF
GENE MUTATION.
 Mutations occur in two ways:
 A) Spontaneous mutation- occurs without an
eogenous mutagen.
 B)Induced mutation- arise because a mutagen
has reacted with parental DNA.

6. ERRORS IN DNA
REPLICATION.
 Tautomeric shift

7.  TAUTOMERISATIONS THAT TAKE PLACE.

8.  ERRORS DURING REPLICATION RESULTS IN:
 A) Spontaneous mutation
 Substitution of on base pair by the other.
 1. transition :-
 Purine to purine or pyrimidine to pyrimidine
substitution.
 2. tranvwersion :-
 Purine to pyrimidine or vice versa.

10.  B) Frameshift mutation:
 Addition or deletion of a base pair that occurs within a
protein coding region of a gene have the effect of
shifting the translatioanal reading frame

11. WHAT IS MUTAGEN?
 They are physical or chemical agents that
increases the occurrence of mutations.
 They can be both physical and chemical
mutagens.
 A) Physical mutagens: UV radiations, heat,ioniing
radiations.
 B) chemical mutagens:
 Act as base analogues, acts directly on DNA or
indirectly on DNA.

12. TYPES OF MUTATIONS.
 1) Somatic mutations: genes mutating in somatic
tissues.
 2) germinal mutations: mutation arises in specific
tissues set aside during development for the
formation of gametes.

14.  2) Heriditary versus acquired mutations:

15.  3) Forward and backward mutations:

16.  4)Missense and nonsense mutations:

18.  4) Silent and neutral mutation:

19.  Neutral mutations:
 Codon specifies different but functionally equivalent
amino acids and not alter protein function is called
neutral mutation.
 5) CONDITIONAL MUTATIONS:

20. CONCLUSION.
 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.
 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.”

21.  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 as
cancer, diabetes and asthma, are linked to
genetic mutations.