1. Mutations

2. What is a mutation?
Changes in the genetic material

3. Mutations can occur in two different types of Cells:
1. Somatic (body) cells
2. Gamete (sex or germ) cells

4. Mutations in somatic cells
Usually result in killing that body cell only.
An exception to this is if the mutation occurs to the DNA that controls regulation of the cell cycle. This can result in cancer.
Benign v. Malignant
Somatic mutations usually do not affect the individual.
Somatic mutations can NOT be passed on to the next generation.

5. Mutations that occur in Gametes:
Gametes (sex or germ) cells
Every cell of the developing fetus/baby will have that mutation
Gamete mutations usually do affect the individual with some genetic disorder
Gamete mutations can be passed on the next generation

6. Two Types of Mutations 2. Chromosomal Mutations 1. Gene Mutations
A. Point Mutations
B. Frameshift Mutations
A. Deletion
B. Duplication
C. Inversion
D. Translocation
E. Non-disjunction

7. Gene Mutations: Small Scale Mutations
Point Mutation
Sickle cell hemoglobin is due to a single base substitution
Example: usually effect no more than one amino acid
THE FAT CAT ATE THE RAT
THE FAT CAT ATE THE HAT

8. Sickle cell

9. Frameshift Mutation
A single nitrogen base is deleted or inserted from the DNA sequence causing a shift in the “reading frame” of the genetic message.
Frameshift is usually more dramatic
May change every amino acid that follows the point of insertion or deletion
THE FAT CAT ATE THE RAT
TEF ATC ATA TET HER AT

10. Chromosomal Mutations
Deletion- loss of all or part of a chromosome
Duplication-production of extra copies of parts of the chromosome
Inversion- reverses the direction of parts of a chromosome
Translocation- part of one chromosome breaks off and attaches to another chromosome
Non-disjunction- means “not coming apart”. When homologous chromosomes fail to separate properly during meiosis (cell division producing gametes)

11. Chromosomal mutations: Large Scale mutations

12. Non-disjunction- Chromosomal mutation
A karyotype generally has two chromosomes at each position (23 pairs)
Trisomy (3) means a person has an extra chromosome
Monosomy (1) means a person is missing a copy of a chromosome.

13. Trisomy 21- Down Syndrome Karyotype Notation? Sex?

14. Klinefelter’s Karyotype Notation? Sex?

15. Turner’s Syndrome Karyotype notation? Sex?

16. Mutations and Natural Selection
Examine the diagram
Does natural selection work on the genotype or phenotype?
Natural selection leads to a change in the “population” NOT the individual.