Download Mutations

Mutations
Mutation—mistake in the DNA that causes
errors in protein production.
Point mutation—mistake at a single
point in the DNA.
*insertion—extra base(s)
*deletion—lacking base(s)
*substitution—different base(s)
Point mutation con’t
Insertion
Should be: AAT TAG CCA GCG
But is
: AAT ATA GCC AGC G
An extra base has been
inserted where it should not
be, causing a frameshift mutation.
What amino acids are formed?
Point mutation con’t
Deletion
Should be: ATA TTA TAG CGA
But is: ATT TAT AGC GA
The A from the original strand of DNA is missing
causing a frameshift mutation.
What amino acids are
formed?
Point mutation
con’t
Substitution
Should be: ACC GTA CTA ATT
But is
: ACC CTA CTA ATT
The C has substituted
Where there should be a G.
What amino acids are formed?
Chromosomal Mutations
• Deletion—part of a chrosome is missing.
• Duplication—creates extra copies of parts
of chromomosomes.
• Inversion—reverse the direction of parts of
the chrosomomes.
• Translocation—part of one
chrobreaksmosome off and attaches to
another.
Significance of Mutations
• Most are neutral (no problem, no benefit)
• Some can cause dramatic effect on
proteins created (big problem) (Can I use
baby powder instead of flour for my cake?)
• But some may be very beneficial, and
provide a source for genetic variability (I
substituted chocolate for nuts, and this
cake is the best I’ve ever had!)