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the error frequency in base pairing is 5 x 10-10 per base pairing
event. Insertion or deletion mutations
• Errors in DNA replication: addition or loss of nucleotides
• Occur at regions in DNA where nucleotide pair repeated
• During replication either the template strand or newly
synthesize DNA strand “slips”
• Template strand slips: Deletion, next slide
• Newly synthesized strand slips: Insertion, see Fig. 5-11 Custom Text Loop held in placed by surrounding
complementary base pairing
New DNA New strand
slips 3' 5'
3' GCAAAAACGT GT
5' 5' Template 3' 3'
C TTT GCAAAAACGT 5' A has been copied
A copied again GT Next cell
strand copied 5'
3' 5' 3' 3'
C GCAAAAACGT CGTTTTTGCA
GCAAAAACGT Wild-type TTTTTGCA 3'
5' 5' Next cell
copied 5' 3' CGTTTTTTGCA
5' Insertion mutation Induced mutation
Base substitution mutations Environmental chemical reacts with a base Base structure altered DNA polymerase makes a base-pairing error Mutation • Example of target site modification leading to antibiotic-resistance
that can be explained by induced mutation:
• Erwinia amylovora: Gram -ve rod, close relative of E. coli
• Infects plant...
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This note was uploaded on 10/25/2013 for the course MICB 201 taught by Professor Davidturner during the Fall '12 term at The University of British Columbia.
- Fall '12