Download Genetic code and mutations

GENETIC CODE AND
MUTATIONS
1. COMPLEMENTARY DNA
ORIGINAL DNA STRAND:
T A T A T A C A A T G C C A G T G G T
T C G C A C A T T
COMPLEMENTARY DNA STRAND:
ATATATGTTACGGTCACCAA
GCGTGTAA
2. mRNA sequence
AUAUAUGUUACGGUCACCAA
GCGUGUAA
A U A U [A U G] U U A, C G G, U C A, C C
A, A G C, G U G, U A A
3. met leu arg ser pro ser val
stop
4. ELEVENTH BASE CHANGED TO C
•T A T A T A C A A T C C C A G T G G
T T C G C A C A T T
• A U A U A U G, U U A, G G G, U C A, C C A, A G C, G
U G, U A A
• Met leu gly ser pro ser val stop
• A change in one base
6. G WERE ADDED TO THE ORIGINAL DNA
STRAND AFTER THE TENTH NUCLEOTIDE
T A T A T A C, A A T, G G C, C A G, T
G G, T T C, G C A, C A T, T
A U A U, A U G, U U A, C C G, G U C, A
C C, A A G, C G U, G U A, A
Met, leu pro val, thr, lys, arg, val ?
Frameshift mutation – due to addition,
deletion or duplication of bases
8. IF THE FIFTEENTH NUCLEOTIDE IN
THE ORIGINAL DNA STRAND WERE
CHANGED FROM G TO C
•T A T A T A C A A T G C C A C T
G G T T C G C A C A T T
• A U A U A U G, U U A, C G G, U G A, C
C A, A G C, G U G, U A A
• Met leu gly stop ……
Frameshift that results in a nonsense
mutation
10. TWENTY-SECOND NUCLEOTIDE IN THE
ORIGINAL DNA STRAND WERE CHANGED
FROM G TO A
T A T A T A C A A T G C C A G T G G T
T C A C A C A T T
A U A U, A U G, U U A, C G G, U C A, C C A, A G U, G
U G, U A A
met leu arg ser pro ser val stop
Point - but silent mutation
MUTATIONS
• What are mutations?
• Any change in the DNA sequence that
may or may not result in a change in
the amino acid sequence.
• How do mutations occur?
• Errors during DNA replication or crossing
over
• Can be triggered by
• Mutagens like X-rays, radioactivity, UV
rays, etc.
• Some mutations are useful. Ex. ??