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Mutations. Mutations. Hollywood’s images of mutation. Mutations. Actual Mutations in fruit flies. 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

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Presentation Transcript
  • Hollywood’s images of


  • Actual Mutations

in fruit flies

what is a mutation
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 mutation

what is a mutation continued
What is a mutation continued
  • A mutation can occur in a chromosome

- a chromosome contains many genes

- chromosomal mutations affect many


Examples: Down Syndrome

Edward’s Syndrome


what causes mutations
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 replications

  • Mutations do not have to be bad (evolution)
critical thinking
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?
kinds of mutations
Kinds of Mutations
  • Substitutions usually affect no more than a single amino acid.
  • Also known as point mutations
kinds of mutations1
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.

kinds of mutations2
Kinds of Mutations
  • In an insertion, an extra base is inserted into a base sequence.
kinds of mutations3
Kinds of Mutations
  • In a deletion, the loss of a single base is deleted and the reading frame is shifted.
knowledge check
Knowledge Check
  • What is a point mutation? Example?
  • What is a frameshift mutation? Example?
chromosomal mutations
Chromosomal Mutations
  • Chromosomal mutations involve changes in the number or structure of chromosomes.
  • Chromosomal mutations include deletions, duplications, inversions, and translocations.
chromosomal mutations1
Chromosomal Mutations
  • Deletions involve the loss of all or part of a chromosome.
chromosomal mutations2
Chromosomal Mutations
  • Duplications produce extra copies of parts of a chromosome.
chromosomal mutations3
Chromosomal Mutations
  • Inversions reverse the direction of parts of chromosomes.
chromosomal mutations4
Chromosomal Mutations
  • Translocations occurs when part of one chromosome breaks off and attaches to another.
critical thinking1
Critical Thinking
  • If Down Syndrome is characterized by having 3 copies of the 21st chromosomes, would it be explained by a gene or chromosomal mutation? Which specific type of gene or chromosomal mutation? Why?
significance of mutations
Significance of Mutations
  • Many mutations have little or no effect on gene expression.
  • Some mutations are the cause of genetic disorders.
    • Cancer
    • Down Syndrome