Figure 2.—

Clk mutants have increased life span and mobility span. To determine whether the slowing of physiologic rates and development resulted in early immobility and thus a reduced health span, we examined the mobility span of Clk mutants. The mobility span was defined as the period of time where a worm exhibited voluntary, directional movement. Wild-type N2 worms remain mobile for most of their life span and become immobile only 1–2 days before they die. With the exception of clk-2 worms, the Clk mutants exhibited increased mobility spans compared to wild-type worms (dark shading). The Clk mutants also exhibited increased survival in a state of immobility compared to N2 worms (light shading). In the bar graph, the height of the darkly shaded bar indicates the mobility span, the height of the lightly shaded bar indicates the period of immobility, and the total bar height indicates the life span.