1. Slide 1 of 24 Copyright Pearson Prentice Hall 12-4 Mutations 12–4 Mutations

2. Slide 2 of 24 Copyright Pearson Prentice Hall 12-4 Mutations Mutations are changes in the genetic material.

3. 12–4 Mutations Slide 3 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Gene mutations - produce changes in a single gene chromosomal mutations - produce changes in whole chromosomes

4. 12–4 Mutations Slide 4 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Gene mutation point mutations - occur at a single point in the DNA sequence. Substitutions Insertions deletions.

5. 12–4 Mutations Slide 5 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Substitutions usually affect no more than a single amino acid.

6. 12–4 Mutations Slide 6 of 24 Copyright Pearson Prentice Hall Kinds of Mutations The effects of insertions or deletions are more dramatic. The addition or deletion of a nucleotide causes a shift in the grouping of codons. Changes like these are called frameshift mutations.

7. 12–4 Mutations Slide 7 of 24 Copyright Pearson Prentice Hall Kinds of Mutations In an insertion, an extra base is inserted into a base sequence.

8. 12–4 Mutations Slide 8 of 24 Copyright Pearson Prentice Hall Kinds of Mutations In a deletion, the loss of a single base is deleted and the reading frame is shifted.

9. 12–4 Mutations Slide 9 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Chromosomal Mutations Chromosomal mutations involve changes in the number or structure of chromosomes. Chromosomal mutations Deletions Duplications Inversions translocations.

10. 12–4 Mutations Slide 10 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Deletions involve the loss of all or part of a chromosome.

11. 12–4 Mutations Slide 11 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Duplications produce extra copies of parts of a chromosome.

12. 12–4 Mutations Slide 12 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Inversions reverse the direction of parts of chromosomes.

13. 12–4 Mutations Slide 13 of 24 Copyright Pearson Prentice Hall Kinds of Mutations Translocations occurs when part of one chromosome breaks off and attaches to another.

14. 12–4 Mutations Slide 14 of 24 Copyright Pearson Prentice Hall Significance of Mutations Many mutations have little or no effect on gene expression. Some mutations are the cause of genetic disorders.

15. 12–4 Mutations Slide 15 of 24 Copyright Pearson Prentice Hall Significance of Mutations Beneficial mutations may produce proteins with new or altered activities that can be useful. Polyploidy is the condition in which an organism has extra sets of chromosomes.

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