, Point mutation:
• Caused often by chemicals or malfunction of DNA replication.
• Exchange a single nucleotide with another
• These changes are classified as transition or transversion
Insertion: Addition of one or more extra nucleotides
into DNA; usually caused by transposable elements.
Deletion: Removal of one or more extra nucleotides into DNA
Inversion: When a gene sequence inverts
and inserts back into the original sequence,
it is known as inversion mutation.
,Substitution: It occurs when other nucleotides
(one or more) replace the nucleotides of a
gene. Sometimes, substitution may add a new
codon to the gene.
Duplication: The mutation is known as
duplication when some nucleotides or a single
nucleotide are duplicated or copied in a gene
sequence.
Other types of gene mutations:
Forward mutation:
Genetic Mutation from wild-type to mutant or evolution of new mutation from wild-
type allele is known as a forward mutation. The forward mutation leads to the
evolution of new traits in the population.
Backward mutation:
Since mutation is a unidirectional phenomenon, some mutation gives the original
(wild-type) allele back to the population, such mutation is known as a backward or
back mutation.
, Silent mutation:
A silent mutation is when a mutation leads to changing
the triplet codon but codes for the same amino acid as
the wild-type one, such mutation is known as silent
mutation. We can say, it is a type of non-expressive one
that doesn’t have any significant effect on the
phenotype.
Mis-sense mutation:
The missense mutation is defined as an origin of a new
codon by a mutation that makes the wrong amino acid
for the protein. Resultantly, a wrong, truncated or
partially functional protein is formed.
Nonsense mutation:
The nonsense mutation is defined as the addition of a
stop codon to the gene or DNA sequence thereupon
stops protein translation. The stop codon, in a
translation, gives the signal to terminate protein
synthesis. The resulting protein by nonsense mutation
is a premature or truncated protein product.
• Caused often by chemicals or malfunction of DNA replication.
• Exchange a single nucleotide with another
• These changes are classified as transition or transversion
Insertion: Addition of one or more extra nucleotides
into DNA; usually caused by transposable elements.
Deletion: Removal of one or more extra nucleotides into DNA
Inversion: When a gene sequence inverts
and inserts back into the original sequence,
it is known as inversion mutation.
,Substitution: It occurs when other nucleotides
(one or more) replace the nucleotides of a
gene. Sometimes, substitution may add a new
codon to the gene.
Duplication: The mutation is known as
duplication when some nucleotides or a single
nucleotide are duplicated or copied in a gene
sequence.
Other types of gene mutations:
Forward mutation:
Genetic Mutation from wild-type to mutant or evolution of new mutation from wild-
type allele is known as a forward mutation. The forward mutation leads to the
evolution of new traits in the population.
Backward mutation:
Since mutation is a unidirectional phenomenon, some mutation gives the original
(wild-type) allele back to the population, such mutation is known as a backward or
back mutation.
, Silent mutation:
A silent mutation is when a mutation leads to changing
the triplet codon but codes for the same amino acid as
the wild-type one, such mutation is known as silent
mutation. We can say, it is a type of non-expressive one
that doesn’t have any significant effect on the
phenotype.
Mis-sense mutation:
The missense mutation is defined as an origin of a new
codon by a mutation that makes the wrong amino acid
for the protein. Resultantly, a wrong, truncated or
partially functional protein is formed.
Nonsense mutation:
The nonsense mutation is defined as the addition of a
stop codon to the gene or DNA sequence thereupon
stops protein translation. The stop codon, in a
translation, gives the signal to terminate protein
synthesis. The resulting protein by nonsense mutation
is a premature or truncated protein product.
