Mutations

• What is the definition of mutation?-A mutation is a change or any mistake in DNA sequence

Mutants…

Types of mutations:

• Point Mutations• Frameshift Mutations• Chromosomal Mutations

Point mutations:

• Point mutations are single-base changes in a gene’s DNA sequence.

• These include: -Missense mutations -Nonsense mutations -Silent mutations

Point mutations: Missense mutation

• Missense mutation: Change in a single amino acid within a protein.

• This does change in protein.Example:

Normal: THE DOG BIT THE CAT Mutated: THE DOG BIT THE CAR

Point Mutations: Nonsense mutation

• Nonsense mutation: Nonsense mutations make a premature stop codon that causing the protein to be shortened.

• Nonsense mutation does change the resulting protein.

Example: Normal: THE DOG BIT THE CAT Mutated: THE DOG BIT

Point Mutations: Silent mutation

• Silent mutation: Silent mutations change the DNA sequence(not the amino acid sequence).

• Silent mutation does not change the resulting protein and no effect on an organism.

Example: Normal: THE DOG BIT THE CAT Mutated: THE DOG BIT THE KAT

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Frameshift Mutations

• Frameshift Mutations: Frameshift Mutation is insertion or deletion of one or more bases into or from the DNA sequence.

• This effect on every amino acid in the protein and it makes protein nonfunctional.

Example:

Frameshift Mutation:

Chromosomal Mutations:

4 types of chromosomal Mutations:• Translocation: A chromosomal segment is

transferred to a new position on the same or another chromosome

• Deletion: the loss or absence of one or more nucleotides from a chromosome

• Inversion: Part of a chromosome breaks out and is reinserted backwards

• Insertion: Part of the chromosome is broken off and attaches to the sister chromatid.

Chromosomal Mutations:

Causes of Genetic Mutations:

• Sometimes it happens for no reason (Spontaneous Mutations).

• Environmental Causes: -UV light - Radiation - X-rays -Some Chemicals

Genetic Disorders:

Cystic Fibrosis

Osteogenesis Imperfecta

Multiple Neurofibromastosis

• genetically-inherited disorder• Multiple begins tumors that form in

skin

Klinefelter’s Syndrome• Males have XXY sex chromosomes:

Twin-to-Twin Transfusion Syndrome

• Due to placental abnormality, one twin receives too much blood and the other does not receive enough.

Fragile X Syndrome