1. Mutations in DNA

2. Mutations A mutation is a change in a DNA sequence. Can happen if – There is a mistake in replication. – Bases change spontaneously due to random movement of atoms in the DNA molecule. – In contact with chemicals, radiation, or ultraviolent rays. They make more frequent errors in base pairing.

3. Types of Mutations – Point Mutations or Substitutions: bases are mismatched GAG CTC GAG Valine Correct DNA Correct mRNA Correct AA GCG CTC GGG Glycine A should pair with T, but instead G is mismatched to T Point mutation mutated mRNA Wrong AA

6. Mutations Example: Sickle Cell Anemia http://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_06

7. Insertion: one or more new nucleotide pairs are inserted into a gene. Correct DNA: ATA CCG TGA TAT GGCACT Correct mRNA: UAU GGCACU Correct amino acids: Tyrosine Glycine Threonine Extra inserted base shifts how we read the codons (3 bases), which changes the amino acids Frameshift mutation ATGACC GTG A in DNA:TACTGGCACT Mutated mRNA:UACUGGCACU Wrong amino acids: Tyrosine Tryptophan Histadine

9. Deletion- One or more nucleotide pairs are deleted.

10. Mutations If a mutation happens in a sex cell (sperm or egg), it may be passed on to future generations. Frameshift Mutation: Deletions and insertions of one or two nucleotides can have catastrophic effects on genes because all the codons that follow the deletion or insertion will be altered.

11. Example THE DOG SAW THE CAT or THD OGS AWT HEC AT

12. Overall Types of Mutations add to the bottom of note sheet Missense : ANY mutation that alters the codon so as to produce an altered amino acid in the protein Nonsense : ANY mutation that changes a codon that specified an amino acid to one of the STOP codons Silent : ANY mutation that causes no change in the protein and cannot be detected without sequencing the gene

13. Four Outcomes of Nucleotide Substitutions 1.The protein may be unchanged. 2.The new protein may be equivalent to the original one. 3.Protein function may be changed by an altered amino acid sequence. 4.Protein function may be destroyed by a premature stop codon.

14. Rate of Mutations in Human Gametes. In humans, mutation rates range from about 1 in every 100,000 gametes to 1 in 1,000,000 gametes.

15. Mutations to control genes can transform one body part into another. Scientists have studied flies carrying Hox mutations that sprout legs on their foreheads instead of antennae!

16. Sickle Cell Anemia http://evolution.berkeley.edu/evolib rary/article/0_0_0/mutations_06 http://evolution.berkeley.edu/evolib rary/article/0_0_0/mutations_06 Name Mutations http://www.nature.ca/genome/04/0 413_e.cfm