Download Mutations

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
Frameshift
oDeletion
oInsertion
Point Mutations
A 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=s
ubstitution+mutation&oq=substitution+mutation&aq=f&aqi=g2g-m2g-S2gmS4&aql=&gs_sm=3&gs_upl=143846l154213l1l154699l15l15l0l1l0l0l130l1254l11.3l14l0&gs_l=img.3..0l2j0i5l2j0i24l2j0i5i24l4.143846l154213l1l154699l15l15l0l
1l0l0l130l1254l11j3l14l0.&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=2421a2169344ff01&biw=1366&bih=587
http://ghr.nlm.nih.gov/handbook/illustr
ations/nonsense
http://www.google.com/search?tbm=isch&hl=e
n&source=hp&biw=1366&bih=587&q=substitut
ion+mutation&gbv=2&oq=Substitution+&aq=2
&aqi=g10&aql=&gs_sm=3&gs_upl=1121l5088l
0l9607l13l13l0l5l5l0l97l689l8l8l0&gs_l=img.3.2
.0l10.1121l5088l0l9607l13l13l0l5l5l0l97l689l8l8
l0.#hl=en&gbv=2&tbm=isch&q=silent+mutation
&revid=656048553&sa=X&ei=gotiT4CkAqjx0g
Gb37yGCA&ved=0CEAQ1QIoAw&bav=on.2,o
r.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=substi
tution+mutation&gbv=2&oq=Substitution+&aq
=2&aqi=g10&aql=&gs_sm=3&gs_upl=1121l5
088l0l9607l13l13l0l5l5l0l97l689l8l8l0&gs_l=i
mg.3.2.0l10.1121l5088l0l9607l13l13l0l5l5l0l9
7l689l8l8l0.#hl=en&gbv=2&tbm=isch&q=miss
ense+mutation&revid=1708114894&sa=X&ei
=3ItiT6qNDsXg0QH3jeGNCA&ved=0CD0Q1
QIoAA&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&f
p=2421a2169344ff01&biw=1366&bih=587
Frame Shift
Either 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.
her
The princess looked beautiful in dress.
Deletion
u
The princess looked beatifuli nh erd ress.
Frame Shift
Guess which type of mutation…
was
The princess was beautiful in her dress.
looked
Substitution
The princess looked very beautiful in her dress.
Insertion
Types of Chromosomal
Mutations
Inversion
Chromosomal
Deletion
Translocation
Duplication
Inversion
Occurs 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
Translocation
Chromosomal abnormalities which occur
when chromosomes break and the
fragments rejoin to other chromosomes
In a balanced translocation,
pieces of chromosomes are
rearranged but no genetic
material is gained or lost in the
cell
http://ghr.nlm.nih.gov/handbook/illustrations/balancedtranslocation
Duplication
A 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
across
The duck swam the pond.
Chromosomal Deletion
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_G
enome/posters/chromosome/hbb.shtml