1. Mutations

2. General Information Definition: Causes: Effects:
A mutation is a change in the structure or amount of genetic material of an organism
Causes:
Can occur naturally as a mistake (sometimes DNA polymerase doesn’t catch all mistakes)
Mutagens in environment (radiation, chemicals)
Effects:
May harm, help, or have no effect

3. How Can Mutations Occur?
They can be inherited from a parent (hereditary mutation)
Mutation present in egg or sperm cell
As the zygote divides, mutation is copied into the DNA of almost every cell in the body.
Is present throughout a person’s lifetime

4. How Can Mutations Occur?
They can be acquired over a person’s lifetime (somatic mutation)
De Novo (new): When mutation occurs just after fertilization. Person has mutation in every cell, but they didn’t inherit it from parent.
Somatic: When mutation occurs in DNA of certain cells during a person’s life. Can be caused by environmental factors such as UV radiation (skin cancer). Cannot be passed to next generation

5. Kinds of Mutations THE – CAT – ATE – THE – RAT
Point Mutation (substitution)
A change of a single nucleotide in a sequence from one kind of base to another
Normal
DNA
THE – CAT – ATE – THE – RAT
Mutated
DNA
THE – BAT – ATE – THE – RAT

6. Kinds of Mutations THE – CAT – ATE – THE – RAT
Frameshift Mutation (deletion/insertion)
When a nucleotide is inserted or deleted, the sequence may be read as different codons
Normal
DNA
THE – CAT – ATE – THE – RAT
Mutated
DNA
THE – ATA – TET – HER – AT

7. How do Mutations effect certain Traits?
Remember:
Traits are expressed by proteins
Proteins are chains of amino acids
Amino acids are determined by codons on mRNA
mRNA is transcribed from DNA
IF there is a mutation on the strand of DNA
mRNA will be transcribed incorrectly
The wrong amino acid will be linked to the chain
The resulting protein, if any, will be useless
The trait won’t be expressed properly

8. Ex: Sickle Cell Anemia
This causes the red blood cells to clot, which leads to a lot of pain
A genetic disorder in which abnormal amounts of the protein hemoglobin causes red blood cells to have a sickle shape.