1. Genetic code and mutations

2. 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:
A T A T A T G T T A C G G T C A C C A A G C G T G T A A

3. 3. met leu arg ser pro ser val stop
mRNA sequence
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
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. 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

5. 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

6. 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
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

7. 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

8. 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. ??