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Mutation

What is that?

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A mutation is actually

  • A change in a persons DNA sequence

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Mutations can be inherited or a person can get them from lifestyle choices

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What Are Mutations?

  • Changes in the nucleotide sequence of DNA. The A, T, C, G pattern.

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  • May occur in somatic cells. Somatic cells are all the cells of the body except the reproductive cells, so the mutation CANNOT BE passed to offspring.

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  • May occur in gametes (eggs & sperm) and CAN be passed to offspring

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Are Mutations Helpful or Harmful?

  • Mutations happen regularly

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  • Almost all mutations are neutral

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  • Chemicals & UV radiation cause mutations

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  • Many mutations are repaired by enzymes

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Are Mutations Helpful or Harmful?

  • Some type of skin cancers and leukemia result from somatic mutations
  • Some mutations may improve an organism’s survival (beneficial)

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What lifestyle choices cause mutations?

  • Environmental factors
    • Sunlight (AND tanning beds too!)
    • Workplace exposure (wood dust)
    • Household exposure (Vap, cigarette, wood smoke, VOC’s)
    • Nuclear radiation (medical)
    • Pollution (vehicle exhaust, soot/ash)

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WHERE IS THE DIFFERENCE IN THE SEQUENCE BELOW?

ATG GTG CAC CTG ACT CCT GAG GAG AAG TCT GCC GTT ACT

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ATG GTG CAC CTG ACT CCT GTG GAG AAG TCT GCC GTT ACT

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Does 1 letter make a difference?

  • What amino acid does GAG code for?
  • What amino acid does GTG code for?

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What is the difference for a person?

Sickle Cell Disease

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3 ways DNA can be altered

  • Substitution (aka. Point Mutation)– one base pair is replaced by another

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  • Insertion – one or more base pairs is added to the DNA

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  • Deletion – one or more base pairs is lost from the DNA

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What are the consequences of a mutation

  • Silent mutation – When a base pair is substituted but the change still codes for the same amino acid

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  • Substitution – When a base pair is substituted and the new codon codes for a different amino acid

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  • Premature Stop – When a substitution results in the formation of a stop codon before all the codons have been read and translated by the ribosome

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  • Codon deletion or insertion (point mutation) – A whole new amino acid is added, or one is missing from the normal protein

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  • Frame Shift – When a deletion or insertion results in a different base pair being the beginning of the next codon, changing the whole sequence of amino acids.