DNA Fingerprinting.ppt

DNA Fingerprinting.ppt

• 1.
  DNA Fingerprinting
• 2.
  Why Use DNAFingerprinting?  DNA fingerprinting is a way of telling individuals of the same species apart  DNA sequences are variable and can therefore be used as identifying characteristics.  DNA fingerprinting has advantages over other sources of evidence (fingerprints, blood type, etc.): – Highly accurate. – Can be gathered from trace crime scene evidence.
• 3.
  How do youtake a DNA fingerprint?  One way: Restriction Fragment Length Polymorphisms (huh?)  aka RFLP  Restriction enzymes are molecules that can cut DNA into pieces --> each enzyme cuts at a very specific DNA sequence  While all human beings share roughly the same DNA sequence, there are in fact a small number of differences  these differences can be seen by restriction enzymes
• 4.
  RFLP Animation
• 5.
  Individual 1 A BC D E DNA
• 6.
  Individual 2 A BC D
• 7.
  Individual 1 vs.Individual 2 A B C D Individual 2 A B C D E Individual 1
• 8.
  Summary  Essentially, oncethe DNA has been cut by the enzymes, we will have DNA fragments of various sizes  Each individual’s banding patterns should be different because the restriction enzymes will cut each person’s DNA at different points  Fragments of different sizes will travel different distances along a gel when an electric current is passed through it
• 9.
  Agarose Gel Electrophoresis Differentbanding patterns from different individuals