Transcript Original DNA Sequence

GENE REGULATION
• Gene regulation: The ability of an organism to
control which genes are transcribed in response to
the environment.
MUTATION
• Mutation: a permanent change that occurs in a
cell’s DNA.
• Can range from changes in a single base pair (Ex:
An A instead of a C) in the coding sequence of
DNA to the deletion of large pieces of
chromosomes.
• http://www.youtube.com/watch?v=efstlgoynlk
POINT MUTATION
• Involve a chemical change in just one base pair.
• A point mutation is exchanged for another is called
a substitution.
POINT MUTATION
• Missense mutation: codes for the wrong amino acid.
• Nonsense mutation: change the codon for an amino acid
to a stop codon.
• Silent mutation: a substitution that does not change the
amino acid.
• Normal Sentence: THE BIG FAT CAT ATE THE WET RAT
• Missense Mutation: THE BIZ FAT CAT ATE THE WET RAT
• Nonsense Mutation: THE BIG RAT.
INSERTION MUTATIONS
• Insertions are additions of a nucleotide to the DNA
sequence.
• This changes the multiples of three in the DNA
sequence from the point of the insertion.
DELETION MUTATIONS
• Deletion mutations remove a nucleotide from the
DNA sequence.
• This changes the multiples of three in the DNA
sequence from the point of the insertion.
INSERTION & DELETION MUTATIONS
• Normal Sentence: THE BIG FAT CAT ATE THE WET RAT
• INSERTION: THE BIG ZFA TCA TAT ETH EWE TRA
• DELETION: THB IGF ATC ATA TET HEW ETR AT
• These mutations are called frameshift mutations
because they change the “frame” of the amino
acid sequence.
DUPLICATION MUTATION
• A duplication mutation is the repeat of one or more
codons.
DUPLICATION MUTATION
• Normal Sentence: THE BIG FAT CAT ATE THE WET RAT
• Duplication: THE BIG FAT FAT CAT ATE THE WET RAT
• Original DNA Sequence:T A C A C C T T G G C G A C G A C T …
• mRNA Sequence:
A U G, U G G, A A C, C G C, U G C, U G A
• Amino Acid Sequence:
Met
Try
Asp
Arg
Cys
Stop
• Mutated DNA Sequence #1
T A C A T C T T G G C G A C G A C T…
What’s the mRNA sequence? A U G, U A G, A A C, C G C, U G C, U G A(Circle the
change)
• What will be the amino acid sequence?
Met STOP Asp
Arg
Cys
Stop....
• Will there likely be effects? YES What type of mutation is this? Base substitution of T for C
causing a NONSENSE mutation.