Download Mutations

Mutations
Changes in the genetic material of
an organism
Types of Mutations
Gene Mutations
1) Point mutations:
changes or
substitutions in
one or a few
nucleotides in the
sequence of DNA.
- usually affect a
single amino acid
in the protein.
Gene Mutations contd
2) Frameshift Mutations:
When a nucleotide is
either inserted or
deleted from the
sequence in the DNA.
- By changing the
position of codons,
these mutations may
change every amino
acid the follows the
mutation.
Example of a deletion frameshift mutation
Types of Mutations cont’d
Chromosomal Mutations: Changes in the number or structure
of chromosomes (large sections of DNA)
Structural:
Chromosomal Mutations
Numerical:
 Aneuploids: Nondisjunction

Polyploidy is the condition in which an
organism has extra sets of chromosomes
– (3n, 4n)
Significance of Mutations
A source of genetic variability in a species; most
are harmful, some can be beneficial (envt.
selects).
 Many mutations have little or no effect on gene
expression.(silent)
 mutations are the cause of genetic disorders.
– (hemophilia, Alzheimer's, cystic fibrosis, cancer, etc.)

Beneficial mutations may produce proteins with
new or altered activities that can be useful in
particular environments.