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  • Anole Lizards: An Example of Speciation

    Anole Lizards: An Example of Speciation

    Animation

    (2 min 38 sec) This animation features the anole lizards as an example of how a single species can split and multiply into many different species with distinct traits.

  • Gene Switch

    Gene Switch

    Animation

    (1 min 15 sec) Regulatory "switches" are found upstream from a gene. Regulatory molecules bind to the switches and recruit RNA polymerase to bind to the gene's promoter region, increasing the transcription of the gene into messenger RNA.

  • Paintbrush Gene

    Paintbrush Gene

    Animation

    (49 sec) In two related Drosophila species, a so-called paintbrush gene is activated to "paint" the pigment on the body. In one species, an extra switch activates the gene, resulting in spotted wings.

  • Pitx1 Expression

    Pitx1 Expression

    Animation

    (55 sec) In the stickleback fish, pelvic-fin reduction resulted from changes in the regulatory switch elements of the Pitx1 gene. In the marine ancestor, the Pitx1 gene is activated in the pelvic-fin region during development to generate the fin. In the pelvic-reduced stickleback, the regulatory switch that normally turns on the Pitx1 gene is either missing or non-functional.

  • Pocket Mouse Evolution

    Pocket Mouse Evolution

    Animation

    (1 min 5 sec) This simulation shows the spread of a favorable mutation through a population of pocket mice. Even a small selective advantage can lead to a rapid evolution of the population.

  • Pocket Mouse and Predation

    Pocket Mouse and Predation

    Animation

    (20 sec) The rock pocket mouse is found in two color variants, or morphs: light and dark. In different environments, their visibility to predators such as owls varies. The dark morph is more vulnerable on light sandy desert, and the light morph on dark lava rock.

  • Wing Morph

    Wing Morph

    Animation

    (29 sec) This "morph" animation demonstrates how the expression of a particular toolkit gene in a butterfly larva corresponds to the location of the wing eyespots in an adult butterfly.

  • The Y Chromosome

    The Y Chromosome

    Animation

    (2 min 46 sec) The Y chromosome has been likened to a hall of mirrors because its sequence contains many sections that appear to be palindromes. These palindromes provide a clue to some interesting events that may have occurred during the course of the chromosome's evolution.

  • Evolution of the Y Chromosome

    Evolution of the Y Chromosome

    Animation

    (5 min 39 sec) How did the human Y chromosome become so small relative to its X counterpart? This animation depicts the 300-million-year odyssey of the sex chromosomes that began when the proto X and Y were an identical pair.