Lesson 7
Mutations
Mutations
What is meant by "jumping genes"?
What is meant by "jumping genes"?
Mutations Explained
Mutations Explained
DNA Mutations
DNA Mutations
Types of Mutations
Types of Mutations
Silent mutation: a mutation that does not result in a change in the amino acid coded for and, therefore, does not cause any phenotypic change
Silent mutation: a mutation that does not result in a change in the amino acid coded for and, therefore, does not cause any phenotypic change
Missense mutation: a mutation that results in the single substitution of one amino acid in the resulting polypeptide
Missense mutation: a mutation that results in the single substitution of one amino acid in the resulting polypeptide
Nonsense mutation: a mutation that converts a codon for an amino acid into a termination codon
Nonsense mutation: a mutation that converts a codon for an amino acid into a termination codon
Substitution: the replacement of one base in a DNA sequence by another base
Substitution: the replacement of one base in a DNA sequence by another base
Deletion: the elimination of a base pair or group of base pairs from a DNA sequence
Deletion: the elimination of a base pair or group of base pairs from a DNA sequence
Insertion: the placement of an extra nucleotide in a DNA sequence
Insertion: the placement of an extra nucleotide in a DNA sequence
Frameshift mutation: a mutation that causes the reading frame of codons to change, usually resulting in different amino acids being incorporated into the polypeptide
Frameshift mutation: a mutation that causes the reading frame of codons to change, usually resulting in different amino acids being incorporated into the polypeptide
Mutation Examples
Mutation Examples
Normal sequence: GCU AAG CUU GAG UAU
Normal sequence: GCU AAG CUU GAG UAU
ala lys leu glu tyr
ala lys leu glu tyr
Silent mutation: GCU AAG CUU GAA UAU
Silent mutation: GCU AAG CUU GAA UAU
ala lys leu glu tyr
ala lys leu glu tyr
Regardless of the one letter change, the amino acid did not change!
Regardless of the one letter change, the amino acid did not change!
Missense mutation: GCU AAG CAU GAG UAU
Missense mutation: GCU AAG CAU GAG UAU
ala lys his glu tyr
ala lys his glu tyr
The one letter change resulted in a different amino acid!
The one letter change resulted in a different amino acid!
Nonsense mutation: GCU AAG CUU GAG UAA
Nonsense mutation: GCU AAG CUU GAG UAA
ala lys his glu stop
ala lys his glu stop
Let us pretend that our sequence is much longer, the single letter change caused for a termination codon to appear!
Let us pretend that our sequence is much longer, the single letter change caused for a termination codon to appear!
Frameshift mutation: GCU AAG (C)UUG AGU AU
Frameshift mutation: GCU AAG (
ala lys leu ser unknown
ala lys leu ser unknown
The deletion of the letter C, caused for the sequence to shift into a new order.
The deletion of the letter C, caused for the sequence to shift into a new order.
GCU AAG CCU UGA GUA U
GCU AAG CCU UGA GUA U
ala lys pro stop
ala lys pro stop
The insertion of the letter C, caused for the sequence to shift into a new order AND caused for a termination codon to appear!
The insertion of the letter C, caused for the sequence to shift into a new order AND caused for a termination codon to appear!
DNA Damage and Repair
DNA Damage and Repair
Sickle Cell Anemia
Sickle Cell Anemia
Blue Eyes?
Blue Eyes?
Mutations you may not know about!
Mutations you may not know about!