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Laboratory : Unit 4: PCR for T-RFLP (pages 83-84) Lecture : Terminal Restriction Fragment Length Polymorphism (T-RFLP) Analysis In-Class Writing : peer review editorial (xlii & 96) Read : manual pages 71-100, 213 Hand In : flow chart 4; editorial draft
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Laboratory: Unit 4: PCR for T-RFLP (pages 83-84) Lecture: Terminal Restriction Fragment Length Polymorphism (T-RFLP) Analysis In-ClassWriting: peer review editorial (xlii & 96) Read: manual pages 71-100, 213 HandIn: flow chart 4; editorial draft DueNext Class: editorial (page 96)
T-RFLP analysis: PCR of 16S rRNA genes. One fluorescently labeled primer & one unlabeled primer one end of amplicon labeled. PCR product contains mixture of different amplicons (16S rRNA genes from each bacterial species.
T-RFLP analysis measures length & quantity of labeled (terminal) restriction fragments. Unlabeled restriction fragments ignored. Amplicons purified to remove reaction buffer, unincorporated primers & dNTPs.
Agarose gel electrophoresis confirm amplicon length (~880-940 bp). Measure concentration of PCR product (1 ml) using nanodrop spectrophotometer.
Digest 100 ng of PCR product with: RsaI (GT/AC) MspI (C/CGG) Digested DNAs analyzed by capillary electrophoresis. Separates DNA molecules that differ by 1 nucleotide.
Instrument uses size standards with different fluorescent tag to estimate size of labeled restriction fragments. Estimates may differ from true length by several nucleotides.
mixed templates: PCR primers: Fam-labeled 8-27F unlabeled 926-907R PCR:
AluI AluI AluI AluI AluI AluI Digest with AluI Fam-labeled AluI restriction fragments
Capillary electrophoresis: Fluorescence intensity Fragment length (nucleotides)