A new research from Colorado State University has suggested that genes, which were previously thought to be non-functional, are in fact working at a low level.
According to the research team, this phenomenon, which was previously undetected, may help answer questions about chronic disease and aging.
Out of 25,000 human genes identified by science, half are believed to be silent at any particular time and activated only when needed. However, Andre Ptitsyn, biomedical and computer expert at the Center for Bioinfomatics at Colorado State University has discovered that current tools cannot measure extraordinarily low levels of gene expression signals.
"Genes that we have believed to be silent are actually whispering," said Ptitsyn.
Ptitsyn applied a common physics principle to find oscillating patterns of gene expression in genes previously thought to be shut off. Most of the studies excluded these 'off' genes from analysis in early stages of research. But with the present study, genes expressed below the current measurements show the pattern of expression coordinated with other genes.
The physics principle used is of stochastic resonance in a computer algorithm. Stochastic resonance seems to be counterintuitive, but it is used to detect weak signals by searching for consistent patterns in stronger (but unrelated) signals.
This principle was applied in gene measurement and it was found that their expressions form a pattern over time of peaks and valleys according to certain rhythms, such as daily circadian rhythm. The silent genes have a rhythm that is detectable as it follows the rhythm of expression of active genes.
Microarrays measure gene expression, but steps are taken to filter out data that seems to be background noise or extra, unexplained low levels of data that scientist previously thought didn't indicate gene expression.
Ptitsyn observed the background data and found that the unexplained data was the expression of "off" genes, or whispering genes. He isolated the genes that were believed to be off and studied the patterns of the background "junk signals" overlapping with the genes that are active and expressing at a known level.
The rhythms dominating expression of active genes, called circadian or daily rhythm, are still clearly detectable among the silent genes. When measured, the timing for increasing and decreasing junk signals coordinates with other interacting genes, both active and silent, that perform the same function.
According to Ptitsyn, this discovery will help science build better microarrays, which are currently used to measure gene activity genes, and will help find expressions previously hidden.
"These findings provide scientists with a technological advancement to detect and measure gene activity previously ignored. The ability to study and measure these genes changes our entire perspective on biology," said Ptitsyn.
"The fact that as many as half of the genes in the human body that have been previously ignored do, indeed, have a role in our bodies changes everything. They are not off, they are on a dimmer switch turned down low. Their role in aging and disease is yet to be discovered, but we could expect that they have an effect," he added.
The study was published in PLoS ONE, a scientific journal.