Like watchmakers, biologists have hunkered down over their respective model organisms, meticulously seeking out biological timekeepers, the genes important for regulating life's internal clock. Up until now, classical approaches had not uncovered the finest details of the machinery that synchronizes life processes with light and darkness, let alone how these rhythms affect behavior and metabolism. "[They] haven't identified genes other than the main components such as the central transcription factors," says Paul Etter at the University of Arizona, Tucson. He and adviser Mani Ramaswami recently wrote a review on the topic.1
Now, full genome sequences for such creatures as the fruitfly and mouse have allowed these so-called chronobiologists to pull off the clock's proverbial face and reveal the intricate inner workings. The verdict: It's still pretty complicated in there. Sophisticated tools such as the microarray, however, offer new power in screening for genes that cycle over time. Indeed, within the ...
