Definition: Any change in the nucleotide sequence of DNA

What Causes It?1. Changes in the environment OR mutagens (other sources of mutation are

physical and chemical agents)

a. Ultraviolet Light (UV)

b. X-Rays

c. Tar from tobacco

d. Pollutants and chemicals

2. Errors during replication, transcription or translation

Chromosomal vs. Gene Chromosomal Mutations: take

place when the number of chromosomes changes or when structural changes occur in the chromosomes

Gene Mutations: a permanent change in the DNA sequence that makes up a gene

Types of Gene Mutations

Point oSubstitution

FrameshiftoDeletionoInsertion

Point MutationsA point mutation is when a single base pair is altered.

http://en.wikipedia.org/wiki/Point_mutation

Substitution

The replacement of one base or nucleotide by another

Silent Mutation: Substitution mutation that has no effect

Missense Mutation: Changes of a single nucleotide that does change the amino acid coding

Nonsense Mutation: Change in an amino acid codon into a stop codon

http://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1366&bih=587&q=substitution+mutation&gbv=2&oq=Substitution+&aq=2&aqi=g10&aql=&gs_sm=3&gs_upl=1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0&gs_l=img.3.2.0l10.1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0.#hl=en&gbv=2&tbm=isch&sa=1&q=substitution+mutation&oq=substitution+mutation&aq=f&aqi=g2g-m2g-S2g-mS4&aql=&gs_sm=3&gs_upl=143846l154213l1l154699l15l15l0l1l0l0l130l1254l11.3l14l0&gs_l=img.3..0l2j0i5l2j0i24l2j0i5i24l4.143846l154213l1l154699l15l15l0l1l0l0l130l1254l11j3l14l0.&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=2421a2169344ff01&biw=1366&bih=587

http://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1366&bih=587&q=substitution+mutation&gbv=2&oq=Substitution+&aq=2&aqi=g10&aql=&gs_sm=3&gs_upl=1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0&gs_l=img.3.2.0l10.1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0.#hl=en&gbv=2&tbm=isch&q=silent+mutation&revid=656048553&sa=X&ei=gotiT4CkAqjx0gGb37yGCA&ved=0CEAQ1QIoAw&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=2421a2169344ff01&biw=1366&bih=587

http://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1366&bih=587&q=substitution+mutation&gbv=2&oq=Substitution+&aq=2&aqi=g10&aql=&gs_sm=3&gs_upl=1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0&gs_l=img.3.2.0l10.1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8l0.#hl=en&gbv=2&tbm=isch&q=missense+mutation&revid=1708114894&sa=X&ei=3ItiT6qNDsXg0QH3jeGNCA&ved=0CD0Q1QIoAA&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=2421a2169344ff01&biw=1366&bih=587

http://ghr.nlm.nih.gov/handbook/illustrations/nonsense

Frame ShiftEither addition or

deletion of one or two nucleotide bases. When this occurs, the “reading

frame” is changed so that all the codons read after the mutation are

incorrect.

http://evolution.berkeley.edu/evolibrary/article/mutations_03

Deletion & Insertion Deletion: To remove one or more

nucleotides in a gene Insertion: Adding one or more

nucleotides into a gene

Mutations involving the deletion or insertion of one or more nucleotides in a

gene often have disastrous effects.

Insertion

Deletion

http://evolution.berkeley.edu/evolibrary/article/mutations_03 http://learn.genetics.utah.edu/archive/mutations/mutatedna.html

Guess which type of mutation…Normal:

The princess looked beautiful in her dress.

The princess looked beautiful in dress.

The princess looked beatifuli nh erd ress.

her

u

Deletion

Frame Shift

Guess which type of mutation…

The princess was beautiful in her dress.

The princess looked very beautiful in her dress.

was

lookedSubstitution

Insertion

Types of Chromosomal Mutations Inversion

Chromosomal Deletion Translocation Duplication

InversionOccurs when a chromosome breaks in two places and the resulting piece of DNA is reversed and re-inserted

into the chromosome Pericentric inversions: inversions that

involve the centromere Paracentric inversions: inversions that do

not involve the centromere

http://ghr.nlm.nih.gov/handbook/illustrations/inversion http://evolution.berkeley.edu/evolibrary/article/history_20

Chromosomal Deletion Occurs when a chromosome

breaks and some genetic material is lost

http://ghr.nlm.nih.gov/handbook/illustrations/chromosomaldeletion

TranslocationChromosomal abnormalities which occur

when chromosomes break and the fragments rejoin to other chromosomes

http://ghr.nlm.nih.gov/handbook/illustrations/balancedtranslocation

In a balanced translocation, pieces of chromosomes are rearranged but no genetic

material is gained or lost in the cell

DuplicationA duplication occurs when part of a chromosome is copied (duplicated)

abnormally, resulting in extra genetic material from the duplicated segment.

http://ghr.nlm.nih.gov/handbook/illustrations/chromosomalduplication http://www.biology-online.org/2/7_mutations.htm

Guess which type of mutation…

Normal: The duck swam across the pond.

The duck swam across swam across the pond.

Duplication

The duck swam pond the across.

Inversion

The duck swam the pond.

Chromosomal Deletion

across

Guess which type of mutation…

Normal: The duck swam across the pond. It looked tiring.

The duck looked tiring. It swam across the pond.

Translocation

How else do mutations occur?

Errors can occur in the processes of mitosis and meiosis.

Nondisjunction: An accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase.

The result is gametes with abnormal numbers of chromosomes.

http://www.genetic-diseases.net/down-syndrome/

Sickle Cell Anemia Sickle cell anemia is a hereditary

disease that causes red blood cells to be shaped like moons.

This is due to a single amino acid substitution in the hemoglobin protein.

http://www.unitedhealthdirectory.com/diseases-and-conditions/sickle-cell-anemia/ http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/hbb.shtml