4. What Are Mutations?
• Changes in the
nucleotide sequence
of DNA
• May occur in somatic
cells (aren’t passed
to offspring)
• May occur in
gametes (eggs &
sperm) and be
passed to offspring
6. Are Mutations Helpful or
Harmful?
• Some type of skin
cancers and leukemia
result from somatic
mutations
• Some mutations may
improve an organism’s
survival (beneficial)
30. Compare your work with the Original DNA
sequence:
1. Describe the difference between your mutated
DNA sequence and the Original DNA sequence.
2. Did the mRNA also change? If yes, describe
its difference between the original mRNA
transcript.
3. Did the Amino acid sequence also change? If
yes, describe its difference between the original
Amino acid sequence.
32. Gene Mutations
• Change in the nucleotide
sequence of a gene
• May only involve a single
nucleotide
• May be due to copying
errors, chemicals,
viruses, etc.
33. Point Mutation
• Change of a single
nucleotide
• Includes the
substitution of
ONE nucleotide in a
gene
34. Silent Mutation
• change in the DNA sequence of the
gene has no effect on the amino acid
sequence
35. Missense Mutation
• occurs when a single nucleotide base in
a DNA sequence is swapped for
another one, resulting in a different
codon and, therefore, a different amino
acid.
36. Nonsense Mutation
• occurs in DNA when a sequence
change gives rise to a stop codon
rather than a codon specifying an
amino acid.
42. GENE MUTATION
POINT MUTATION
SUBSTITUTION
SILENT MUTATION
NO EFFECT IN
AMINO ACID
SEQUENCE
MISSENSE
MUTATION
GIVE RISE TO
DIFFERENT AMINO
ACID
NONSENSE
MUTATION
GIVE RISE TO A
STOP CODON
FRAMESHIFT MUTATION
INSERTION DELETION