The Hammerling Experiment

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The Hammerling Experiment

• By
• Danny Nemeth
• Michael Leonard
• Allie Wrabel

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Acetabularia

• Danish biologist Joachim Hammerling needed cells
  large enough to operate on conveniently and
  differentiated enough to distinguish the pieces.
• He chose the unicellular green alga Acetabularia,
  which grows up to 5 centimeters, as a model
  organism for his investigations. 
• Just as Mendel used pea plants and Sturtevant
  used fruit flies, Hammerling picked a model
  organism that was suited to the specific
  environmental question he wanted to answer,
  assuming that what he learned could then be
  applied to other organisms. 
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Acetabularia

• Individuals of the genus Acetabularia have
  distinct foot, stalk, and cap regions all are
  differential parts of a single cell.  The nucleus
  is located in the foot.
• As a preliminary experiment, Hammerling amputated
  the caps of some cells and the feet of others.
• He found that when he amputated the cap, a new
  cap regenerated from the remaining portions of
  the cell (foot and stalk). 
• However, when he amputated the foot, no new foot
  regenerated from the cap and stalk.
• Therefore, Hammerling hypothesized that the
  hereditary information resided within the foot of
  Acetabularia. 
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•  

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Surgery on Single Cells

• Testing the Hypothesis
• select individuals from two species of the genus
  Acetabularia
• Caps of cells look different
• A. mediterranea
• Disk shaped cap
• A. crenulata
• branched, flowerlike cap
• 1. Cut the cell into 3 parts (Cap, Stalk, Foot)
• 2. Combine the foot and cap of the cell with the
  stalk of the different cell
• 3. Watch how the cap grows on both cells.
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Conclusion

• The Experiment determined that
• If the caps would grow the same as before,  the
  heredity information would have to be stored in
  the foot of the cell.
• If the cell would have regrown different caps,the
  nucleus would not be found in the foot. 
• Now we understand that genetic instructions pass
  from the nucleus in the foot upward through the
  stalk to the developing cap.

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Thank You For Your Time )