Generating Mutations

Spontaneous vs induced Mutation

Spontaneous= natural copying accidents inside the cell. Induced= caused by outside agents like chemicals or radiation (mutagens)

Depurination

Losing an Adenine (A) or Guanine (G) base, leaving a blank apurinic site in the DNA. Happens naturally thousands of times a day in your cells.

Deamination of Cytosine

Removing an amino group (NH2) from cytosine, which accidentally turns it into Uracil.

Trinucleotide repeat Expansion

DNA copying slips and forms a hairpin loop, accidentally adding extra 3 letter repeats over and over ( causes conditions like Huntingtons disease and fragile X.

Genetic anticipation

Symptoms get more severe and show up at an earlier age in younger generations as repeat expansions keep getting longer.

Intercalationg Agents

Chemical mutagens (like profalvin) that wedge right between DNA base pairs, distorting the helix and causing insertion/ deletion error during copying.

Radiation Therapy and Radio protectors

Radiation intentionally damages DNA to stop cancer cells from dividing. Radion protectors (like amifostine) help shield healthy tissues from radiation damage.

The Ames test

a lab test using mutant salmonella bacteria ( that cant make histidine) to see if a chemical causes mutations by forcing the bacteria to revert and grow.