1. Genetic Mutations

2. Genetic Changes What is a mutation?
A mistake or change in the genetic (DNA) make-up of an organism
Can occur during replication, transcription or translation!
There are several different types of mutations
Point mutations (substitutions)
Frameshift mutations (insertions or deletions)
Chromosomal mutations (involving more than one base pair)
Spontaneous mutations (happen randomly)
Mutation Story

3. Point & Frameshift Mutations
Point mutation (substitution)
Change in a single base pair in DNA
THEDOGBITTHECAT
Change the ending “T” to a “R”
THEDOGBITTHECAR
Missense mutation: the mutation changes the amino acid
Silent mutation: the mutation does NOT change the amino acid
Nonsense mutation: the mutation changes the amino acid to a “STOP”

4. Nonsense vs. Missense Mutations
The new codon causes an incorrect amino acid to be inserted into the protein. The effects on the function of the protein depend on what is inserted in place of the normal amino acid.
NONSENSE
The new codon causes the protein to prematurely terminate, producing a product that is shortened and often does not function.

5. Deletion / Insertion A shift in one place (frameshift mutation)
HAVEANICEDAY
- Delete the “N” and shift everything down
HAVEAICEDAY
- Add another “N” and shift everything up
HAVEANNICEDAY

6. Chromosomal Mutation Trisomy Chromosomes are physically changed
May break and rejoin incorrectly
May not separate correctly (or at all) during Meiosis  NONDISJUNCTION
Trisomy
Example of a chromosomal mutation in which a zygote ends up with an extra chromosome (Down Syndrome

7. Types of chromosomal mutations:
Deletion of all or part of a chromosome.
Duplication repeats a segment of a chromosome.
Inversion is when part of a chromosome becomes oriented in the reverse of its usual direction.
Translocation is when part of one chromosome breaks off and attaches to another, non-homologous chromosome.

8. Duplication
Repeats a segment of a chromosome

9. Inversion
part of a chromosome gets reversed

10. Translocation
part of one chromosome breaks off and attaches to another, non-homologous chromosome

11. Inheritance of Mutations
Mutations that occur in sex cells are passed on to the organism’s offspring and will be present in every cell of the offspring.
Somatic cell mutations are NOT passed on to the next generation

12. Spontaneous Mutations
Occur randomly
Some environmental agents causes
Prolonged exposure to X-rays
Prolonged/excessive exposure to UV radiation
Radiation exposure
Certain chemicals