1. DNA Insertion
Group 2

3. Extra
Nucleotide

4. What is DNA
Insertion?

5. DNA Insertion
In genetics, an insertion (also called
an insertion mutation) is the addition of
one or more nucleotide base pairs into a
DNA sequence. This can often happen in
microsatellite regions due to the DNA
polymerase slipping. Insertions can be
anywhere in size from one base pair
incorrectly inserted into a DNA sequence
to a section of one chromosome inserted
into another.

6. N Region Addition is the addition of
non-coded nucleotides during
recombination by terminal
deoxynucleotidyl transferase.
P Nucleotide Insertion is the
insertion of palindromic sequences
encoded by the ends of the recombining
gene segments.

7. Effects of DNA
Insertion

8. Effects of DNA Insertion
• Insertions can be particularly
hazardous if they occur in an exon,
the amino acid coding region of a gene.
A frameshift mutation, an alteration in
the normal reading frame of a gene,
results if the number of inserted
nucleotides is not divisible by three, i.e.,
the number of nucleotides per codo.
Frameshift mutations will alter all the
amino acids encoded by the gene
following the mutation.

9. Usually, insertions and the subsequent
frameshift mutation will cause the
active translation of the gene to
encounter a premature stop codon,
resulting in an end to translation and the
production of a truncated protein.

10. These truncated proteins frequently are
unable to function properly or at all and
can possibly result in any number of
genetic disorders depending on the gene
in which the insertion occurs.

11. In-frame insertions occur when the
reading frame is not altered as a result of
the insertion; the number of inserted
nucleotides is divisible by three. The
reading frame remains intact after the
insertion and translation will most likely
run to completion if the inserted
nucleotides do not code for a stop codon.

12. However, because of the inserted
nucleotides, the finished protein will
contain, depending on the size of the
insertion, multiple new amino acids that
may affect the function of the protein.