Mutations Hollywoods images of mutation Mutations Actual Mutations in fruit flies What is a mutation A mutation is any change in a cells DNA A mutation can occur in an individual gene ID: 238672
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Slide1
MutationsSlide2
Mutations
Hollywood’s images of
mutationSlide3
Mutations
Actual Mutations
in fruit fliesSlide4
What is a mutation?
A mutation is any change in a cell’s DNA
A mutation can occur in an individual gene
- results in a single changed protein
- cystic fibrosis a mutation in
the protein that makes a type of ion channels in cell membrane - bacterial resistance to antibiotics is an example of a beneficial gene mutationSlide5
What is a mutation
continued
A mutation can occur in a chromosome
- a chromosome contains many genes
- chromosomal mutations affect many proteins
Examples: Down Syndrome Edward’s Syndrome Cri-du-ChatSlide6
What Causes Mutations?
Can be caused by
mutagens
- a physical or chemical cause of mutation. Examples: UV light, radiation, drugs, and benzene.
Mutagens are often also carcinogens – anything that causes cancer
Can be natural, random events. - mutations occur in 1/100,000 DNA replicationsMutations do not have to be bad (evolution)Slide7
Critical Thinking
Will all mutations have a dramatic impact on an individual? How do you know? Which types of mutations do you think will have the greatest impact on an organism?Slide8
Gene MutationsSlide9
Kinds of Mutations
Substitutions
usually affect no more than a single amino acid.
Also known as
point mutationsSlide10
Kinds of Mutations
The effects of
insertions
or
deletions are more dramatic.The addition or deletion of a nucleotide causes a shift in the grouping of codons.
Changes like these are called frameshift mutations.Slide11
Kinds of Mutations
In an insertion, an extra base is inserted into a base sequence.Slide12
Kinds of Mutations
In a deletion, the loss of a single base is deleted and the reading frame is shifted.Slide13
Knowledge Check
What is a point mutation? Example?
What is a
frameshift mutation? Example?Slide14
Chromosomal Mutations
Chromosomal mutations involve changes in the number or structure of chromosomes.
Chromosomal mutations include deletions, duplications, inversions, and translocations.Slide15
Chromosomal Mutations
Deletions involve the loss of all or part of a chromosome.Slide16
Chromosomal Mutations
Duplications produce extra copies of parts of a chromosome.Slide17
Chromosomal Mutations
Inversions reverse the direction of parts of chromosomes.Slide18
Chromosomal Mutations
Translocations occurs when part of one chromosome breaks off and attaches to another.Slide19
Critical Thinking
If Down Syndrome is characterized by having 3 copies of the 21
st
chromosomes, would it be explained by a gene or chromosomal mutation? Which specific type of gene or chromosomal mutation?
Why?Slide20
Significance of Mutations
Many mutations have little or no effect on gene expression.
Some mutations are the cause of genetic disorders.
Cancer
Down Syndrome