...Cole M. McQueen; Emily E. Schmitt; Tapasree R. Sarkar; Jessica Elswood; Richard P. Metz; David Earnest; Monique Rijnkels; Weston W. Porter The molecular clock plays key roles in daily physiological functions, development and cancer. Period 2 (PER2) is a repressive element, which inhibits...

... embryo. The discovery of the cyclic expression of several genes, occurring every 90 minutes in each presomitic cell, has shown that there is a molecular clock linked to somitogenesis. We demonstrate that a dynamic expression pattern of the cycling genes is already evident at the level of the prospective...

... tens of millions of years after an initial branching. Various attempts to date those branchings by using molecular clocks have disagreed widely. While the timing of the evolution of the developmental systems of living metazoan body plans is still uncertain, the distribution of Hox and other...