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Normal DNA Strand
DNA : TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT
mRNA:
AUG UUU CCU GCU CAU CAA AUU CGU UCU UAA
Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop
Mutation
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Mutation – Any change in the DNA base
sequence which leads to a change in a
protein. Sometimes mutation are
beneficial, but they usually lead to nonfunctioning or incorrectly functioning
proteins.
Point Mutation – One base in
sequence is changed
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Original DNA: TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT
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Original Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop
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4th triplet in DNA, first base C changed to G
Mutated DNA: TAC AAA GGA GGA GTA GTT TAA GCA AGA ATT
Incorrect mRNA: AUG UUU CCU CCU CAU CAA AUU CGU UCU UAA
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Mutated Protein: Met-Phe-Pro-Pro-His-Glu-Ile-Arg-Ser-Stop
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The 4th amino acid is proline instead of alanine
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Point
Mutation
Frameshift Mutation – One base added
or deleted from the DNA sequence
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Original DNA: TAC AAA GGA CGA GTA GTT TAA GCA AGA ATT
Original Protein: Met-Phe-Pro-Ala-His-Glu-Ile-Arg-Ser-Stop
2nd triplet in DNA, first base A deleted
Mutated DNA: TAC AAG GAC GAG TAG TTT AAG CAA GAA TT
Incorrect mRNA: AUG UUC CUG CUC AUC AAA UUC GUU CUU AA
Mutated Protein: Met-Phe-Leu-Leu-Ile-Lys-Phe-Val-Leu
After the second amino acid, the protein is completely
different
Frameshift Mutation
The bottom line about DNA…
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No DNA = No Protein = No Cells = No Life
Reproduction is all about passing DNA
from one cell to another and from one
generation of organisms to the next