What are they? Changes in a single DNA base.

Mostly neutral or harmful, and sometimes lethal.

• No major effect because they aren’t involved in making proteins.
• Example: Imagine if you got a typo in the white space of your assignment. Your teacher might not notice it because it doesn't change the message!

• Same-Sense Mutations

  • Changes one codon for an amino acid into another codon but still codes for the same amino acid.
  • Real-world Example: It's like saying "Hello" or "Hi". Different words but the same greeting!
  • How is this possible? Due to the redundancy of the genetic code. So, AGC to AGT both mean "Hey, make a serine!"
  • These mutations don't affect the phenotype. But, can pave the way for a future mutation.

• Nonsense Mutations

  • Converts a normal codon into a stop codon.
  • Real-world Example: Imagine reading a book, and mid-sentence, there's a full stop. Confusing, right?
  • Result? The protein gets cut short and usually malfunctions. The aftermath? Depends on the job of that protein!

• Mis-sense Mutations

  • Changes one amino acid in a protein.
  • Impact? Depends!
    • If the new amino acid is like its old roommate (similar properties), things might be okay.
    • But, if not? Trouble ensues. For instance, sickle cell disease is a mean result of such mutations.
  • Silver Lining? A tiny fraction of these mutations can actually boost protein function, kinda like a surprise superhero transformation! Though rare, these are evolution's little gifts!