Apical Ectodermal Ridge - Relevant Experiments

Relevant Experiments

  • AER Maintains Limb Outgrowth through FGF secretion, Mesenchyme Cells Determine Identity:

These experiments reveal that the limb mesenchyme contains the necessary information concerning limb identity, but the AER is needed to stimulate the mesenchyme to live up to its destiny (of becoming an arm, leg, etc.)

  1. When the AER is removed, limb development halts. If an FGF bead is added in the AER’s place, normal limb development proceeds.
  2. When an extra AER is added, two limbs form.
  3. When forelimb mesenchyme is replaced with hindlimb mesenchyme, a hindlimb grows.
  4. When forelimb mesenchyme is replaced with non-limb mesenchyme, the AER regresses, and limb development halts.
  5. When the AER from a late limb bud is transplanted to an earlier limb bud, the limb forms normally. The converse – transplantation of an early limb bud to a late limb bud – also results in normal limb development. However, the underlying mesoderm in the progress zone ‘’is’’ fate specified. If progress zone mesoderm is transplanted along with the AER, then additional finger/toes are formed (for an early-->late transplantation) or the finger/toes are formed too early (for a late-->early transplantation).
  • AER Formation Relies on Dorsal-Ventral Boundary:

The Precise Microenvironmental Cues present at the D-V boundary are crucial for AER formation

  1. When the limb bud is dorsalized - in limbless mutants, for example - and no dorsal-ventral boundary exists, the AER is unable to form and limb development halts.

Read more about this topic:  Apical Ectodermal Ridge

Famous quotes containing the words relevant and/or experiments:

    “Don’t give your opinions about Art and the Purpose of Life. They are of little interest and, anyway, you can’t express them. Don’t analyse yourself. Give the relevant facts and let your readers make their own judgments. Stick to your story. It is not the most important subject in history but it is one about which you are uniquely qualified to speak.”
    —Evelyn Waugh (1903–1966)

    “The man who invented Eskimo Pie made a million dollars, so one is told, but E.E. Cummings, whose verse has been appearing off and on for three years now, and whose experiments should not be more appalling to those interested in poetry than the experiment of surrounding ice-cream with a layer of chocolate was to those interested in soda fountains, has hardly made a dent in the doughy minds of our so-called poetry lovers.”
    —John Dos Passos (1896–1970)