Download Mutations

Mutations
A Mutation is a change in
genetic material
There are 2 types of mutations
Gene mutations
– Produce a change in a single gene
Chromosomal mutations
– Produce a change in a whole chromosome
Gene Mutations
 Point mutation
 Mutations involving one or only a few
nucleotides.
– Includes when one base is changed to another,
– And when one base is inserted or removed from the
DNA sequence.
 Equivalent to changing one letter in a sentence
– original The fat cat ate the wee rat
– mutation The fat hat ate the wee rat
Gene Mutations
 Frameshift mutation
 When one or more bases are added or removed.
This causes the reading frame to change or shift.
– This can result in a meaningless and often shortened
protein.
 Equivalent to adding or removing letters in a
sentence.
– original The fat cat ate the wee rat
– mutation The fat caa tet hew eer at (t in cat deleted)
Chromosomal Mutations
Deletion
Affect the whole chromosome
Can be small, like the removal of one
codon sequence, or larger like the removal
of an entire gene on the chromosome.
One example is the removal of a word.
– original The fat cat ate the wee rat
– mutation The fat ate the wee rat
Chromosomal Mutations
Duplication
When one part of the chromosome gets
copied and inserted back into the
chromosome.
An example is when a word is duplicated
in a sentence.
– original The fat cat ate the wee rat
– mutation The fat cat cat ate the wee rat
Chromosomal Mutations
Inversion
An entire section of DNA is reversed.
– May involve only a few bases or several genes
Equivalent to part of a sentence being
flipped around or inverted
– original The fat cat ate the wee rat
– mutation The fat tar eew eht eta tac
Chromosomal Mutations
 Translocation
 When part of one chromosome swaps places with
part of another chromosome.
 This would be the same as if two sentences broke
apart and recombined with each other.
– original The fat cat ate the wee rat
The big dog ran
– mutation The fat cat ate dog ran
The big the wee rat
Mutations
 Most mutations have little or no effect on gene
expression.
 Mutations that cause dramatic changes can be
harmful and disrupt normal biological activities.
Mutations
 Mutations may also
produce proteins that
have new or altered
activities that can be
useful.
 This is most often
seen in plants and
animals.
 Polyploid plants are
often larger and
stronger than diploid
plants.
Polyploidy
 Polyploidy is the
condition in which an
organism has extra
 Gametes produced
may be triploid (3N)
or tetraploid (4N).
sets of chromosomes.
 This happens when a
complete set of
chromosomes fails to
separate during
meiosis.
 Some examples of
polyploid plants are
bananas and many
citrus fruits.