BIOL207 L11 Mut Gen PDF

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BIOL207 L11 Mut GenBIOL207 L11 Mut GenBIOL207 L11 Mut Gen...

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Biology 207 Lecture 11 Mutations & genes Dr. Mike Harrington University of Alberta

Lecture 11 - Mutations & genes 1) Codon table 2) Genes 3) Location of mutations in genes 4) Human HBB gene 5) EMS 6) Parsimony 7) Direction

1) Codon Table Shows mRNA sequence from 5’ to 3’ Phenylalanine = Phe = F Stop codon = Ter = X

2) Genes a) BIOL 107 diagrams

b) BIOL 207 diagrams

3) Location of mutations in genes a) Overview Mutations happen anywhere in DNA

b) bp substitutions in protein coding regions

Example: codon changed to codon for different aa: A. silent B. nonsense C. missense

c) Indels in protein coding regions

Example: deletion of 3 bp: A. frameshift B. loss of aa C. gain of aa

d) Mutations in promoters

à no mRNAs

e) Mutations in regulatory regions

à too few or too many mRNAs

f) Mutations at splice sites

à intron left in (or removed wrong) à defective mRNAs

4) Human HBB gene a) Normal function RBCs contain Hemoglobin proteins

MoM: Hemoglobin

β globin HBB 11p15 α globin HBA1 16p13

OGL Fig 39.6

b) A specific mutation causes sickle cell disease Gene: HBB DNA: AT à TA bp substitution mRNA: GAA à GUA at codon 6 protein: GLU6VAL

Camppbell Fig. 17.23

These Hemoglobins form chains when not carrying oxygen

Molecule of the month: Hemoglobin

Campbell Fig 5.21

5) EMS Recall that EMS makes GCàAT bp substitutions. What would happen if EMS mutated a 5'-CTT-3’ codon? A. Glu à Lys B. Glu à Ter C. Leu à Phe D. Leu à Ile

6) Parsimony The simplest explanation is the correct one Mutation: HIS33ARG Which was more likely? A. CACàCGC B. CACàAGG C. both equally likely

7) Direction a) Terminology Forward mutations wild type allele à mutant allele Reverse mutations mutant allele à wild type allele

b) Example Which of these is a reverse mutation?

D. = A and B

E. = B and C

The same is true of indel mutations

Testable content Know how to draw a gene (see the figure) Know the consequence(s) of a mutation happening at different places in a gene (missense, frameshift, etc.) Know how to draw DNA à mRNA à protein and what would happen if there was a mutation in the DNA (HBB example, EMS question, etc.)...