Goal 3 - Mutation Notes
What is a mutation?
Changes in the genetic material (DNA).
Mutations can occur in two different types of cells:
1. Somatic (body) cells
2. Gamete (sex) cells
Mutations that occur in somatic (body) cells usually result in killing that body cell only.
An exception to this is if the mutation occurs to the DNA that controls regulation of the cell cycle. This can result in cancer.
Mutations that occur in gamete (sex) cells means that every cell of the developing fetus/baby will have that mutation.
1. Gene Mutations
2. Chromosomal Mutations
Changes in the genetic material (DNA).
Mutations can occur in two different types of cells:
1. Somatic (body) cells
2. Gamete (sex) cells
Mutations that occur in somatic (body) cells usually result in killing that body cell only.
An exception to this is if the mutation occurs to the DNA that controls regulation of the cell cycle. This can result in cancer.
- Somatic mutations usually do not affect the individual.
- Somatic mutations can NOT be passed on to the next generation.
Mutations that occur in gamete (sex) cells means that every cell of the developing fetus/baby will have that mutation.
- Gamete mutations usually do affect the individual with some genetic disorder.
- Gamete mutations can be passed on to the next generation.
1. Gene Mutations
2. Chromosomal Mutations
Type of Single Gene Mutations - Point
2 types of Single Gene Mutations:
1. Point Mutation: a single point in the DNA sequence is affected.
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino Acid: Met - Arg - Thr - Leu
(In this DNA sequence notice the 5th base in the DNA sequence has been changed)
Mutated Sequence
DNA: TAC GTA TGG AAT
mRNA: AUG CAU ACC UUA
Amino Acid: Met - His - Thr - Leu
Point mutations usually affect no more than a single amino acid. The protein may be slightly affected or not affected at all.
THE FAT CAT ATE THE RAT
THE FAT CAT ATE THE HAT
1. Point Mutation: a single point in the DNA sequence is affected.
- Can be a substitution in which one base is changed into another base.
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino Acid: Met - Arg - Thr - Leu
(In this DNA sequence notice the 5th base in the DNA sequence has been changed)
Mutated Sequence
DNA: TAC GTA TGG AAT
mRNA: AUG CAU ACC UUA
Amino Acid: Met - His - Thr - Leu
Point mutations usually affect no more than a single amino acid. The protein may be slightly affected or not affected at all.
THE FAT CAT ATE THE RAT
THE FAT CAT ATE THE HAT
Types of Gene Mutations - Frame Shift
2. Frameshift Mutation: a single gene or nitrogen base is deleted or added from the mRNA sequence causing a shift in the “reading frame” of the genetic message.
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino Acid: Met - Arg - Thr - Leu
*(Notice in this DNA sequence a T has been added to the sequence after the second base)
DNA: TAT CGC ATG GAA T
mRNA: AUA GCG UAC CUU A
Amino Acid: Iso - Ala - Tyr - Leu
The affect of frameshift mutations is usually more dramatic. Frameshift mutations may change every amino acid that follows the point of the mutation. Frameshift mutations can alter a protein so much that it is unable to perform its normal functions.
THE FAT CAT ATE THE RAT
THE FAT CAT ATE THE RAT
TEF ATC ATA TET HER AT
- Can be an insertion in which one base is inserted in the DNA sequence.
- Can be a deletion in which one base is deleted in the DNA sequence.
DNA: TAC GCA TGG AAT
mRNA: AUG CGU ACC UUA
Amino Acid: Met - Arg - Thr - Leu
*(Notice in this DNA sequence a T has been added to the sequence after the second base)
DNA: TAT CGC ATG GAA T
mRNA: AUA GCG UAC CUU A
Amino Acid: Iso - Ala - Tyr - Leu
The affect of frameshift mutations is usually more dramatic. Frameshift mutations may change every amino acid that follows the point of the mutation. Frameshift mutations can alter a protein so much that it is unable to perform its normal functions.
THE FAT CAT ATE THE RAT
THE FAT CAT ATE THE RAT
TEF ATC ATA TET HER AT
Chromosomal Mutations
5 types of Chromosomal Mutations:
1.Deletion
2.Duplication
3.Inversion
4.Translocation
5.Non-disjunction
Deletion: Involves the loss of all or part of a chromosome.
Duplication: Involves the production of extra copies of parts of the chromosome.
Inversion: Reverses the direction of parts of a chromosome.
Translocation: When one part of a chromosome breaks off and attaches to another chromosome.
Non-disjunction: Means “not coming apart”. When homologous chromosomes fail to separate properly during meiosis.
1.Deletion
2.Duplication
3.Inversion
4.Translocation
5.Non-disjunction
Deletion: Involves the loss of all or part of a chromosome.
Duplication: Involves the production of extra copies of parts of the chromosome.
Inversion: Reverses the direction of parts of a chromosome.
Translocation: When one part of a chromosome breaks off and attaches to another chromosome.
Non-disjunction: Means “not coming apart”. When homologous chromosomes fail to separate properly during meiosis.
- Results in abnormal numbers of chromosomes. Typically you have 2 of each.
- Trisomy (3)means a person has an extra copy of a chromosome.
- Monosomy (1) means a person is missing a copy of a chromosome.