DNA Detective Laboratory

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DNA Detective Laboratory
Background Information
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• DNA Background Information
• DNA stands for Deoxyribonucleic acid.
• Nucleic acids are complex molecules found in all
  cells.
• DNA is a special nucleic acid found in the
  nucleus of a cell.
• DNA is found in nearly all the cells in a human
  body.
• It contains the blueprint for your genetic
  material.
• The coded information is what determines your own
  unique characteristics such as the color of your
  eyes, hair and skin, blood type, and whether or
  not youll have certain diseases.
• Our DNA makes us different from every other
  person on the earth.
• No two people would have the same DNA but related
  people would have similar DNA.

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• DNA BACKGROUND INFO
• If hair, blood, or skin is found at a crime
  scene, the DNA is compared with the the suspects
  to prove guilt or innocence.
• Humans are not the only ones to have DNA.
• The nucleus of all living things contains DNA.
• The cells of plants and animals have differing
  numbers of chromosomes.
• The chromosomes contain genes which are carried
  on the DNA molecules. The genetic code is
  inherited from a persons parents 23 chromosomes
  from the mother and 23 chromosomes from the
  father.
• DNA was discovered in 1952 when Rosalind Franklin
  made the first x-ray of a DNA molecule and found
  it was in the shape of a helix, or spiral. One
  year later American geneticist Francis Crick and
  British biophysicist James Watson built the first
  model of the DNA molecule.
• DNA has two strands of material in the form of a
  tightly coiled, twisted ladder with three billion
  rungs. It is called a double helix. The sides are
  made of sugar and phosphate, the steps or rungs
  are made of pairs of chemicals called nitrogen
  bases.

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• DNA Background Information
• The 4 nitrogen bases are adenine, thymine,
  cytosine, and guanine. They are identified by the
  letters A, T, C, G. Like pieces in a puzzle
  Adenine always binds with thymine, and cytosine
  always binds with guanine.
• DNA is composed of millions of these bases.
• Even though there is only one way for these bases
  to match up, the order in which the pairs are
  arranged, called DNA sequencing, makes each
  person unique (except for identical twins).

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• DNA FINGERPRINTING
• DNA testing has become a popular tool in modern
  criminal investigations.
• In every human being 99 of the genes are the
  same. We all have legs, arms, noses, digestive
  systems, brains, and so on. But the remaining
  one percent of the DNA is unique to that person.
• Since DNA is found in nearly every cell in the
  body, scientists can isolate DNA from blood,
  saliva, skin, or other body tissues when they are
  found at a crime scene.
• To make a DNA fingerprint, an enzyme is used that
  breaks the DNA into pieces. The length and shape
  of these strands depends on a persons genes.
• The pieces are then placed in a gel, through
  which electricity is passed. Then they are
  treated with radiation. An x-ray makes the
  pattern visible, and the result is a DNA
  fingerprint.

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• DNA Investigation
• The FBI has sent the lab 5 samples gathered at a
  recent crime scene. They want DNA testing to be
  done on the samples. They have reason to believe
  that two of the suspects are related and they
  want our lab to find out by comparing the DNA
  fingerprints from the samples.
• Your group will be given 5 paper bags labeled
  A-E. Each bag contains 15 tiles in 4 different
  colors representing the DNA samples. 2 of the
  bags are identical. The 4 different tile colors
  represents the 4 bases of the DNA structure.
• You can only check the contents of a bag by a
  blind draw. You may only pull one tile out at a
  time without looking inside the bag. Record the
  color on the data sheet in your crime lab
  notebook. Then replace that tile into the bag.
  Shake the bag before drawing another tile.
• Your job is to find out which two are similar by
  comparing the samples in each bag and making a
  report to present to the FBI. You will record all
  your group work into the Crime Lab Notebook.

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You May Begin