CHICAGO, July 25 (Xinhua) -- Researchers at Northwestern University (NU) slowed mutant fruit flies'metabolic rates by 50 percent, and the expected detrimental effects of many mutations never manifested.
After experimentally testing fruit flies' many different genetic mutations, the researchers found the same result each time, according to a study published on Thursday in the journal Cell.
"When the flies developed at a normal rate, developmental problems occurred," said NU's Richard Carthew, who led the experimental research. "When we slowed the rate, developmental problems disappeared. They develop slower and grow slower."
"This upends the paradigm of everything we know about development," said NU's Luis Amaral, who led the computational research. "We have always thought that if you 'break' some genes, there will be serious developmental consequences. It turns out that's not true for some genes - as long as you also slow the metabolism of the growing organism."
In the study's most striking discovery, researchers found that fruit flies, with slowed metabolic rates, could live without any microRNAs, which was previously thought impossible.
Found in all plant and animal species, microRNAs play a key role in regulating gene expression. To put it simply: microRNAs control development, physiology and behavior.
The researchers believe that feedback control enables complex systems to adjust performance in order to meet a desired response. After completing hundreds of experiments across several years, the researchers believe that a slower metabolism gives the animals' systems time to correct errors.
"When you look at all the different proteins and genes that interact within a cell, you can get overwhelmed by all the components and the interactions among them," Amaral said. "If you are growing fast and something goes wrong, it can be catastrophic. You need these complex networks because they increase redundancy to prevent catastrophe.
"But if you are growing slowly, you might not need such a complex system," he said. "You have more time to adjust to mistakes and react to changes."
In other words, if you give the system more time, it will eventually get to where it needs to be.
This finding could eventually be applied to cancer, said Northwestern's Richard Carthew, who led the experimental research.
"Tumors are extremely metabolically active," he said. "Tumors soak up an enormous amount of energy, which is why cancer patients are often exhausted. We could potentially think about ways to target the metabolism of cancer cells. Maybe by slowing their metabolic rate, we could stop the oncogenic mutations in tumor cells from expressing their cancer phenotype."
