Human genome project


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Human genome project

  1. 1. The HumanGenomeProjectHolli Cook
  2. 2. What is it? The Human Genome Project was an effort to determine the complete sequence of DNA in the human genome. Its goal was to discover and map all of the approximately 35,000 human genes and make them available for further biological study.
  3. 3. Techniques used: Restriction Fragment Length Polymorphisms Automated DNA Sequencing Polymerase Chain Reaction
  4. 4. Restriction Fragment LengthPolymorphisms (RFLPs) Each restriction enzyme is specific to a certain base sequence, a “restriction site”, and will cut up DNA at all such sites to produce a number of “restriction fragments”. No one will have the exact same base sequence unless they are identical twins. Because of the DNA variability, restriction fragments from a given region of an individual’s genome can be separated using get electrophoresis to reveal a unique pattern (a finger print). Inheritance of RFLPs can be followed through families. By using the RFLPs scientists can create linkage maps.
  5. 5. Step 1: Isolate the DNA To extract DNA from its location, several laboratory procedures are needed to break the cell wall and nuclear membrane. Appropriately separate the DNA from other cell components. When doing so, make sure that the process doesn’t damage the DNA at all.
  6. 6. Step 2: Restriction Digestionand Gel Electrophoresis The extracted DNA is digested with specific restriction enzymes. Each restriction enzyme will recognize and cut up DNA in a predictable way, resulting in a reproducible set of DNA fragments, or restriction fragments, or different lengths.
  7. 7. Step 2: Restriction Digestion and GelElectrophoresis (continued) The millions of restriction fragments produced are commonly separated by electrophoresis on agarose gels.
  8. 8. Step 3: Transfer DNA bySouthern Blotting The gel is denatured in a basic solution and placed in a tray. A porous nylon or nitrocellulose membrane is laid over the gel, and the whole thing is weighted down. All the DNA restriction fragments in the gel are transferred as single strands by capillary action to the membrane. All fragments retain the same pattern on the membrane as on the gel.
  9. 9. Step 4: DNA Hybridization Themembrane with the target DNA is incubated with the DNA probe.
  10. 10. DNA Probe The DNA probe usually comes from a DNA library, which is a collection of vectors that contain a representation of an original DNA molecule cut into pieces. Vectors may be transformed into bacteria and may multiply the piece of DNA they contain many times. The DNA probe is also converted into a single- stranded molecule, conveniently labeled, using any standard method.
  11. 11. Step 4: DNA Hybridization(continued) If strands on the membrane are complementary to those of the probe, hybridization will occur and labeled duplexed formed. If strands are highly stringent, hybridization with distantly related or non-homologous DNA does not happen. The DNA probe picks up sequences that are complementary and ideally homologous to it among the thousands or millions of undetected fragments that migrate through the gel.