Mutations

• Hollywood’s images of mutation

Mutations

• Actual Mutations in fruit flies

What is a mutation?

• A mutation is any change in a cell’s DNA• A mutation can occur in an individual gene - results in a single changed protein - cystic fibrosis a mutation in the protein that

makes a type of ion channels in cell membrane - bacterial resistance to antibiotics is an example

of a beneficial gene mutation

What is a mutation continued

• A mutation can occur in a chromosome - a chromosome contains many genes - chromosomal mutations affect many proteins Examples: Down Syndrome Edward’s Syndrome Cri-du-Chat

What Causes Mutations?

• Can be caused by mutagens- a physical or chemical cause of mutation. Examples: UV light, radiation, drugs, and benzene.

• Mutagens are often also carcinogens – anything that causes cancer

• Can be natural, random events. - mutations occur in 1/100,000 DNA replications• Mutations do not have to be bad (evolution)

Point Mutations

• A single nucleotide is altered. Can change one amino acid in a protein

• Example of a point mutation is a substitution• Milk – Mile• GGACAATCA GGACCATCA proline -valine-serine proline-glycine-serine

Frameshift Mutations

• A nucleotide is either inserted or deleted from a gene.

-all of the triplets from the point of mutation onward will be changed

Frameshift Mutations Insertion

• An insertion occurs when a nucleotide is added to a gene

Example: A nucleotide is inserted The fat cat ate the rat

The faa tca tat eth era t -the extra nucleotide shifts all of the triplets

that follow

Frameshift Mutations Deletions

• A deletion occurs when a nucleotide is removed from a gene.

Example: A nucleotide is removedThe fat cat ate the rat

Thf atc ata tet her at

Insertion• GGACAATCA GCGACAATCA proline -valine-serine arginine-cysteine-stop

Deletion• GGACAATCA GGAAATCA proline -valine-serine proline-leucine

Vocabulary

• Mutation• Mutagen• Carcinogen• Point mutation• Frameshift mutation - insertion - deletion

MutationsChromosomal Mutation:

change in the structure or number of chromosomes in a cell; usually caused by problems during meiosis or a mutagenMutagen:

an agent that causes a DNA mutationEx: UV, radiation…

Chromosomal MutationsDeletion: a mutation in which part of the chromosome or a sequence of DNA is missing

Chromosomal Mutations

Duplication: a mutation in which part of the chromosome or a sequence of DNA is repeated

Chromosomal MutationsInversion: a mutation in which part of the chromosome or a sequence of DNA is flipped or rotated

Chromosomal MutationsTranslocation: a mutation in which part of the chromosome or a sequence of DNA is removed from one chromosome and relocated or attached to another chromosome