1. Types of mutations Mutations are changes in the genetic material
There are two basic types of mutations:
Gene mutations - mutations that produce changes in a single gene
Chromosomal mutations - mutations that produce changes in whole chromosomes

2. Can occur spontaneously
Molecular Genetics
Causes of Mutation
Can occur spontaneously
Chemicals and radiation also can damage DNA.
High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.

3. Molecular Genetics
Hox Genes
Hox genes are responsible for the general body pattern of most animals.

4. Gene mutations Point mutations:
Involves changes in one or a few nucleotides (they occur at a single point in the DNA sequence)
They can be:
Substitutions
Insertions
Deletions

5. Substitutions One base is changed to another
Substitutions usually only affect a single amino acid

6. Insertions and Deletions
A base is either inserted or removed from the DNA sequence
If a nucleotide is added or deleted, the bases are still read in groups of three, so every codon after is changed
These types of mutations cause Frameshift mutations
Can cause major changes to the protein, to the point where it can’t perform its normal function

7. Chromosomal mutations
Involve the chromosomal changes in the number or structure of chromosomes
Can change the locations of genes on chromosomes, and the number of copies of some genes
Four types:
Deletions
Duplications
Inversions
Translocations

8. Duplications and Deletion
Duplication (Nondisjunction):
The failure of a chromosome to separate from its homologue during meiosis
One gamete receives an extra copy of a chromosome and the other lacks it
Deletion:
Loss of a piece of a chromosome

9. Translocations and Inversions
When a chromosome piece breaks off and reattaches to another, nonhomologous chromosome
Inversion:
Chromosome segment breaks off and then reattaches in reverse orientation to the same chromosome

10. Significance of Mutations
Most mutations are neutral (they have little or no effect)
Mutations that cause dramatic changes in protein structure or gene activity can be very harmful
Mutations are a source of genetic variability in a species
Polyploidy- a mutation where an organism has an extra set of chromosomes
Polyploid plants are often larger and stronger

11. Real Mutations
Visible mutations usually required more than one genetic mutation.

12. Down Syndrome: Trisomy 21
Nondisjunction event causing the 21st chromosome pair to not separate during meiosis (Gamete formation)

13. Multi X female (Nondisjunction during egg formation – X chromosomes fail to separate)

14. Muscle protein gene mutation
Muscle protein gene mutation. Causes double the muscle tissue to form resulting in one buff dog… or super strong German Toddler (results from either: Deletion or Missense)

15. Extra Limbs (Chromosal)

16. Color Change Mutations (Thought to be a point mutation)

17. Extra Fingers – Polydactyly (Chromosomal Mutation)

18. Molecular Genetics