1. Chapter 11.6 When it all goes Wrong

2. Mutations: is any change in the nucleotide sequence of DNA.
*Can change in large regions of chromosomes
*Can change a single nucleotide
*Can cause a big change in phenotype

3. There are 2 general categories of gene mutation
1. Base substitution
*Is the replacement of one base or nucleotide with another
*Can cause no change (remember that in the genetic code several amino acids have more than one codon)
*When no change results this is called a silent mutation
Example: Sickle Cell Anemia

5. 2. Base insertion or deletion
*Adding or subtracting is a little more disastrous because of the triplet code.
*All the nucleotide down on the backbone (downstream) would be changed
*Re-group into different condons
*Non-working proteins

6. What causes Mutations?
*Errors made during DNA replication
*Errors made during meiosis (crossing over)

7. Mutagens: physical or chemical agents that cause mutations.
Radiation
X-ray
Ultra violet light
Chemicals that act like DNA bases.

8. Mutations
Are usually harmful (cause death)
Some (very few) are beneficial to certain environments
If mutation is in gametes it will be passed down to offspring
Mutations have caused the greatest diversity in the world around us