Mutations

1. Mutations

2. What is a mutation??? • Change in a sequence of DNA

3. Types of Mutations • Chromosomal mutations – change in the number or structure of chromosomes • Down Syndrome • Point mutations– change in one or more nucleotides that changes the DNA sequence • Sickle Cell Anemia

4. Chromosomal Mutations • Deletion – section of chromosome breaks off and is lost • Duplication – part of the chromosome breaks off and is inserted again • Translocation– part of the chromosome breaks off and is inserted into a different chromosome • Inversion– part of the chromosome breaks off, turns around, and reattaches in reverse order

5. Examples of Chromosomal Mutations Deletion Duplication Inversion Translocation

6. Point Mutations • occurs in only one nucleotide and affects only one codon in a gene • Substitutions = replace a nucleotide for a another • Insertions = add a nucleotide • Deletions = take away a nucleotide

7. Example of Substitution • AAC CCA TTA • AAGCCA TTA • How does this affect the amino acid sequence?

8. Example of Insertion • AAC CCA TTA • ATA CCC ATT ACC • How does this affect the amino acid sequence?

9. Example of Deletion • AAC CCA TTA • ACC CAT TAC • How does this affect the amino acid sequence?

10. Point Mutations • Sickle Cell Disease • Mutation on Chromosome 11 = change in aa sequence of hemoglobin • Tay-Sachs • Mutation on Chromosome 15 = change in sequence of aa in enzymes that break down certain fatty acids • Causes large amounts of fatty acids to build up on nerve cells 1st discoveredin retinas (eye)

11. How are mutations good, bad, or neutral? • Good-change in DNA sequence that leads to better protein production, increasing the organisms chance of survival. • i.e. camouflage • Bad- change in DNA sequence that leads to the wrong protein formed, decreasing the organisms survival • i.e. genetic diseases such as sickle anemia • “Equal”- change in DNA sequence that produces the same correct protein.