1. Mutations

2. Mutations:
A change in the nucleotide sequence of a gene

3. Frameshift Mutation
Caused by insertions (additions) or deletions of nucleotides in DNA
Result  drastically altered protein (possibly non-functional!)

4. TAC AGT TTC AAT ATT
TAC AGT TTC TAA TAT T
AUG UCA AAG AUU AUA A
mRNA codons are shifted!
(c) Methionine – Serine – Lysine – Isoleucine - Isoleucine

5. Point Mutations
Involve change in a single nucleotide (changes a specific codon)
Silent Mutation: A changed codon still codes for the correct amino acid
Ex. UUA  UUG still codes for leucine

6. (b) Nonsense Mutation: Substitution occurs early on in protein chain  malfunctioning protein Ex. UCG  UAG “stop” codon

7. (c) Missense Mutation: Single amino acid is changed  may not have such a drastic effect Ex. CCG  CAG (mRNA) CCG = proline CAG = glutamine * Single change to 150 amino acid protein may have little effect

8. Mutagens
Environmental: Substances in the environment that cause mutations to DNA
Radiational: Ex. Radioactive substances, X-Rays or UV radiation
Chemical: Cigarette smoke, pesticides, pollutants

9. 2 Types of Mutations Somatic Germinal
Occurs in body cell (not including reproductive cells… eggs or sperm)
Mutation occurs in reproductive cells (eggs & sperm)
Can lead to evolutionary change!!