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