ABSTRACT
The prior quote is from a recent issue of Science with a special section on the topic of developmental timing. The temporal events that guide development are key parts of the puzzle of contemporary molecular genetics. Genes are known to turn on at certain times in development; microRNAs show temporal-and tissuespecific patterns of gene expression (cf. Carrington & Ambros, 2003); and genes activate to trigger downstream developmental events removed in time from the triggering event (cf. Gehring & Ikeo, 1999; Marcus & Fisher, 2003). Timing mechanisms are fundamental to the way that inherited elements direct an individual’s growth, whether at the cellular or organism level.
