What is a mutation???
GENETIC MUTATIONS
MISTAKES IN DNA
A MISTAKE CAN BE:
1. A point mutation – substitution, addition,
or removal of a single DNA base.
2. A frameshift mutation – a point mutation
due to an addition or deletion of a DNA base
that causes a major change in the genetic
code.
Sickle cell anemia is caused by a
point mutation - substitution
Val-his-leu-thr-pro-glu-glu
Val-his-leu-thr-pro-val-glu-
Muscular Dystrophy is caused by a
frameshift mutation
THE CAT SAW THE DOG
CHANGE THE W TO A T:
THE CAT SAT THE DOG
CHANGE THE D TO AN H
THE CAT SAW THE HOG
MAJOR MISSENSE: REMOVE THE “C”
THE ATS AWT HED OG
This type of
mutation causes
a protein to be
non-functional.
It is a severe
problem and can
be lethal.
MAJOR MISSENCE: INSERT AN “M” after the
first “The”.
THE MCA TSA WTH EDO G
The body cannot
make sense out of
the incorrect protein,
just as the sentence
no longer makes
sense to you.
Nonsense
• When a point mutation codes for a STOP in
the middle of a sequence. Could be due to any
of the point mutations.
Nonfunctional
dystrophin, the
protein that helps
attach your skeletal
muscle to its
surroundings.
Some mutations involve whole
chromosomes:
1. Deletion: A piece of a chromosome is lost
because of breakage during cell division
Cri du chat
Inversion: A piece of a chromosome
breaks off and reattaches backwards.
The effect can be lethal.
Duplication: A portion of the
chromosome is copied and placed
in the same chromosome.
Translocation: a piece of a
chromosomes breaks off and
reattaches to a non-homologous
chromosome
Non-disjunction: A chromosome
fails to separate from its
homologue during meiosis
Turner’s Syndrome:
Klinefelter’s Syndrome:
Mutations in nature: