Mutation Notes

1. Mutation Notes

2. Mutations – heritable changes in genetic information. • Creates genetic diversity • Point mutations – occur at a single point in the DNA sequence. • 3 Types of Gene Mutations - Substitution - Insertion - Deletion

3. Substitution – one base is changed to a different base. Usually affect no more than a single amino acid or they have no effect at all. - Ex. Original Strand – THE BIG DOG BIT TED AND RAN OFF - Substitution – THE BIG DOG BIT TOD AND RAN OFF

4. 2. Insertion – one base is inserted into the DNA sequence. Effects are dramatic. Ex. THE DBI GDO GBI TTE DAN DRA NOF F 3. Deletion – one base is removed from the DNA sequence. Effects are dramatic. Ex. THE BIG OGB ITT EDA ANR ANO FF - Insertions and deletions are called frameshift mutations because they shift the “reading frame” of the genetic message. - Can change every amino acid that follows the point of the mutation.

5. Chromosomal mutations – involve changes in the # or structure of chromosomes. • Can change the location of genes on chromosomes • Can change the # of copies of some genes.

6. 4 Types of chromosomal mutations • Deletion – loss of all or part of a chromosome • Duplication – extra copy of all or part of a chromosome • Inversion – reverses the direction of parts of a chromosome • Translocation – when part of one chromosome breaks off and attaches to another

7. Some mutations come from mutagens- chemical or physical agents in the environment. • Chemical - pesticides, tobacco smoke, pollution. • Physical - radiation, like X-rays & UV light.

8. Some mutations have little or no effect. • Harmful mutations – ex. cancers, sickle cell disease (causes anemia & severe pain). • Beneficial mutations - pesticide resistant insects like mosquitoes.