
Mutations are changes to the base pair
sequence of the genetic material of an
organism.

Mutations can be caused by copying errors in
the genetic material during cell division, by
exposure to ultraviolet or ionizing radiation,
chemical mutagens, or viruses.

Germ line mutations – can be passed on
to descendants

Somatic mutations – cannot be
transmitted to descendants

Point mutation – where only one base
in the gene is copied incorrectly during
DNA replication. This would be an error
of the DNA-building enzyme, DNA
polymerase.

Point mutation example:
(A) Substitution – exchanges one base for another
example: change in a single “chemical
letter” such as switching an A to a G
C T G G A G
C T G G G G

Frameshift – Since protein-coding DNA is
divided into codons three bases long,
insertions and deletions can alter a gene so
that its message is no longer correctly read or
translated.
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
Frameshift mutations example:
(A) Insertion – extra base pairs are inserted into a
new place in DNA
C T G G A G
C T G G T G G A G

Frameshift mutations example:
(B) Deletion – a section of DNA is lost, or deleted
C T G G A G
C T A G