4.12 DNA and Mutations

Quick DNA Review Base pairing Base pairing

Translation and Codons Codon: 3-nucleotide sequence on mRNA that codes for an amino acid Codon: 3-nucleotide sequence on mRNA that codes for an amino acid

Mutations Mutation: Changes in the genetic material Mutation: Changes in the genetic material A few other notes A few other notes 99.9% of time = BAD or Neutral 99.9% of time = BAD or Neutral Does not give you super powers Does not give you super powers No such thing as Kryptonite No such thing as Kryptonite

2 Types of Mutations Gene Mutations Gene Mutations Chromosome Mutations Chromosome Mutations

Types of Gene Mutations Point Mutation: Point Mutation: Mutation that affects a single nucleotide, usually by substitution. Mutation that affects a single nucleotide, usually by substitution.

Frameshift Mutation: Frameshift Mutation: Mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide Mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide Insertion MutationDeletion Mutation Insertion MutationDeletion Mutation

Remember Codons! Frameshift Mutations: Frameshift Mutations: THE FAT CAT ATE THE RAT Codon TEF ATC ATA TET HER AT

Genetic Mutation

Chromosomal Mutations Chromosomal Mutation: Chromosomal Mutation: Change in the number and structure of chromosomes. Change in the number and structure of chromosomes.

How do mutations occur? 1) Can be inherited 1) Can be inherited 2) Can be aquired 2) Can be aquired A) Environmental agents may damage DNA A) Environmental agents may damage DNA B) Mistakes occur when cell copies its DNA B) Mistakes occur when cell copies its DNA

Significance of Mutations Most mutations are neutral (do nothing) Most mutations are neutral (do nothing) Most of the rest cause defective proteins = genetic disorder or death Most of the rest cause defective proteins = genetic disorder or death

But... (key!!!) A small % may be beneficial. A small % may be beneficial. May produce proteins with new, or altered, activities that can be useful in changing or different environments. May produce proteins with new, or altered, activities that can be useful in changing or different environments.

What happens if mutation is better?