Mutations are changes in genetic material that can be caused by errors in DNA replication or exposure to mutagens like radiation or chemicals. There are two main types of mutations: base substitutions, where one nucleotide is replaced by another, and insertions or deletions, where a nucleotide is added or removed. Base substitutions can be silent if they do not change the resulting protein or missense if they do. Insertions or deletions cause frameshift mutations by changing the triplet codes that encode proteins. Chromosomal mutations involve changes in chromosome number, structure, or position of genes. Mutations are not always harmful and can increase genetic diversity.

1. Mutations

3. Mutations Occur when there is an error in DNA replication Def: Change in genetic material Mutagens Physical or chemical agents that cause mutations Ex: high energy radiation (x-ray or UV) Ex. Chemicals (that are similar to DNA but cause incorrect base pairing)

4. Mutation Any change in the nucleotide sequence of DNA Large or small 2 Main types Base Substitutions (point mutations) Insertions or deletions

6. Usually do not change amino acid

7. Sometimes causes a change in the protein made

8. Silent Mutation

9. When a substitution does not cause a change in the protein expressed by a gene

10. Remember some codons represent the same amino acid

13. More disastrous

14. mRNA is read as triplet codes

15. Adding/removing bases changes these three letter codes

16. Codons downstream from insertion/deletion will be regrouped and probably code for a non-working protein

17. Result: FRAMESHIFT MUTATION

20. May change location of genes on chromosome

21. Include:

22. Deletions: loss of part of chromosome

23. Duplications: produce extra copies of parts of chromosome

24. Inversions: reverse direction of chromosome

26. Mutations NOT always harmful Some alter a protein in a beneficial way that may help species in a specific environment If mutation is present in organisms gametes, it may be passed off to off-spring Mutations are the ULTIMATE source for GENETIC DIVERSITY!!!