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.