DNA Sequencing DNA Fingerprinting

1
DNA Sequencing DNA Fingerprinting

• BIOL 100
• 27 October 2009

2
DNA Sequencing
3
Fig 13.3 p. 260

• Polymerase Chain Reaction (PCR)
• Mimics replication to make multitudes of copies
  of DNA sample quickly
• Cycles of heating and cooling
• Taq polymerase the key to the technique

4
HANDOUTDeoxynucleotides vs. Dideoxynucleotides

• Four treatments in PCR
• Each has large amounts of normal
  deoxynucleotides
• dA, dC, dG, and dT
• Each has Taq polymerase enzyme
• Each has a single type of chain terminator
  dideoxynucleotide
• ddA, ddC, ddG, or ddT

5
Fig. A p. 213
Each band represents millions of copies
terminated by a dideoxynucleotide. Electrophoresis
can separate strands that differ by only one
nucleotide in length.
6
DNA Fingerprinting
7
DNA Fingerprinting

• Relies on VNTRs (variable-number tandem repeats)
• Number of repeats varies by individual
• Chromosomally inherited
• The more repeats, the longer the sequence, the
  slower it will move through electrophoresis gel

8
HANDOUTDNA Fingerprinting
9
HANDOUTHöggren and Tegelström 1995