"It's like a conductor walking away from an orchestra during a performance; each musician continues to play, gradually going out of key with the others," said Ptitsyn. That is one likely reason why researchers previously missed the impact of circadian rhythm on all genes.
Depending upon environmental factors, groups of genes can function in a synchronized manner, shifting in time against each other and working in what resembles a domino effect.
However, very few genes are found to be oscillating in the same phases in different tissues or organs. In fact, only about 5 percent of all genes fall into the same phase or timing of peaks and valleys. Synchronization with the activity of the other genes and genes in different organs is a very important and highly specific part of gene function.
In addition, genes can oscillate with different amplitude -- the swing between the highest and the lowest point. Genes are expressed at very different levels, but most of them have the same relative change throughout the day. However, some genes show significant change in the amplitude in different organs or in response to a changing environment.
"When we standardize genes onto a common scale that measures levels of expression, we could not find a single gene that did not oscillate," Ptitsyn said.
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Contact: Dell Rae Moellenberg
DellRae.Moellenberg@colostate.edu
970-491-6009
Public Library of Science
14-Jun-2007