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.
This animation shows a rotating 3-D image of a stickleback skeleton. The pelvic region, including the pelvic spines, is highlighted in red. Armored plating covers the flanks of the fish. The three prominent dorsal spines give the fish its name.
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.
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.
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...
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.
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.