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Mutations in DNA

Mutations in DNA . 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.

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Mutations in DNA

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

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

  5. Correct DNA: ATA CCG TGA TAT GGCACT Correct mRNA: UAU GGCACU Correct amino acids: Tyrosine GlycineThreonine Extra inserted base shifts how we read the codons (3 bases), which changes the amino acids Frameshift mutation ATG ACC GTG A in DNA: TAC TGG CAC T Mutated mRNA: UAC UGG CAC U Wrong amino acids: TyrosineTryptophan Histadine Insertion: one or more new nucleotide pairs are inserted into a gene.

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

  7. 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.

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

  9. Overall Types of Mutationsadd 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 STOPcodons • Silent: ANY mutation that causes no change in the protein and cannot be detected without sequencing the gene

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

  11. 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.

  12. 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!

  13. Sickle Cell Anemiahttp://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_06 Name Mutations http://www.nature.ca/genome/04/0413_e.cfm

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