Bacterial cells can “remember” short, temporary changes in their bodies and their immediate environment.
And although these changes are not encoded in the cell’s genetics, it still transmits memories of them to its descendants over several generations. This is evidenced by the results of a new study by American scientists, the press service of Northwestern University (USA) reports.
It is noted that this discovery not only challenges long-held assumptions about how simple organisms transmit and inherit physical traits, but also could be used for new medical applications.
For example, researchers could circumvent antibiotic resistance by subtly altering pathogenic bacteria to make their descendants more sensitive to treatment over generations, the paper notes.
According to scientists, the basic assumption in bacterial biology is that hereditary physical characteristics are determined primarily by DNA.
But from a complex systems perspective, we know that information can be stored at the level of the regulatory network between genes. We wanted to investigate whether there are characteristics that are passed from parents to offspring that are encoded not in the DNA but in the regulatory network itself, the researchers note.
The regulatory network is analogous to the communication network through which genes influence each other. The scientists hypothesized that this network might be the key to passing on traits to offspring. To test this hypothesis, they turned to E. coli, a common bacterium and well-studied organism.
In the case of E. coli, the entire organism is a single cell, the researchers say. It has far fewer genes than a human cell, about 4,000 genes as opposed to 20,000. It also lacks the intracellular structures that are known to underlie the constant organization of DNA in yeast and the multiplicity of cell types in higher organisms.
The scientists used a mathematical model of a regulatory network to simulate the temporary deactivation (and subsequent reactivation) of individual genes in E. coli.
They found that these temporary perturbations can lead to long-lasting changes that are predicted to be inherited over generations. The team is currently working to test their models in lab experiments, the paper says.
Trying to explain how changes in the regulatory network can be transmitted across generations, scientists suggest that such a disturbance causes an irreversible chain reaction in it:
- when one gene is deactivated, it affects the gene next to it in the network;
- By the time the first gene is reactivated, the cascade is already in full swing, since genes can form self-sustaining chains that, once activated, become immune to external influences.
“It’s a network phenomenon,” the researchers note. “Genes interact with each other. If you disrupt one gene, it affects the others.”
Although the scientists performed gene deactivation to achieve this, different types of disturbances can cause a similar effect.
We could also change the cell environment, the researchers note. This could be temperature, nutrient availability, or pH.
The study also suggests that other organisms have the necessary elements to detect non-genetic inheritance.
“In biology, it’s dangerous to assume that everything is universal,” says research team leader Adilson Motter. “But intuitively, I expect the effect to be general, because the regulatory network of E. coli is similar or simpler than that of other organisms.”
Bacteria change their shape to become more resistant to antibiotics.
Source: Racurs
I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.