1. Mutations

2. Mutations are random, rare changes in genetic material that can occur during DNA replication
If a mutation occurs in part of DNA that codes for a gene, there could be a change in the characteristics of that organism
Mutations can also occur in whole Chromosomes
Mutations

3. Mutations that occur in somatic cells are NOT passed to offspring
Mutations that occur in gametes (sperm and eggs) ARE passed to offspring
Spiderman experienced what type of mutation?

4. Chromosome Mutations 5 Types of Chromosome Mutations Deletion
Inversion
Translocation
Nondisjunction
Duplication
Chromosome Mutations

5. Due to breakage
A piece of a chromosome is lost
Deletion

6. Inversion Chromosome segment breaks off Segment flips around backwards
Segment reattaches
Inversion

7. Occurs when a gene sequence is repeated
Duplication

8. Translocation Involves two chromosomes that are NOT homologous
Part of one chromosome is transferred to another chromosome
Translocation

9. Nondisjunction Failure of chromosomes to separate during Meiosis
Causes gamete to have too many or too few chromosomes
Nondisjunction

10. Chromosome Mutation Animation

12. Gene Mutations Change in the nucleotide sequence of a gene
May only involve a single nucleotide
Point mutation
May be due to replication errors, chemicals, viruses, radioactive spiders, etc.
Gene Mutations

13. Point Mutations Change of a single nucleotide
Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
Sickle Cell Disease is
the result of one nucleotide
Substitution that changed
one amino acid
Occurs in the
Hemoglobin gene
Point Mutations

14. Types of Gene Mutations
Substitution- one base pair is exchanged for another
Can cause a change in a codon, which DOES NOT result in a change in the amino acid coded for by that codon
This type of mutation is called a Silent Mutation because there is no change in the type of protein that is produced
Types of Gene Mutations

15. Frameshift Mutation Inserting or Deleting one or more nucleotides
Changes the “reading frame” of the gene
Proteins built incorrectly
Original:
The fat cat ate the wee rat.
Frame Shift (“a” added):
The fat caa tet hew eer at.
Frameshift Mutation

16. Types of Gene Mutations
Insertion- an extra base pair is inserted into a new place in the DNA
Types of Gene Mutations

17. Deletion- a base pair or section of DNA is lost or deleted
3 Types of Mutations

18. Amino Acid Sequence Changed

19. Gene Mutation Animation

20. A Mutagenic Factor- anything that can cause a change in DNA
X-Rays and UV rays (high energy radiation) can cause breaks in DNA that are not easily repaired
Chemicals can cause substitutions and changes in DNA that affect the order of amino acids in a polypeptide
Substances that cause changes in DNA leading to cancer are called carcinogens
Mutagenic Factors