PNAS: The world's first discovery! Some microorganisms may change their evolutionary rules through horizontal gene transfer!

October 19, 2020 // -- In a recent study published in the international journal PNAS, scientists from Monash University and others discovered for the first time in the world that certain microorganisms may change the rules of evolution.
the main idea of evolution is the process of genetic or vertical gene transfer (VGT, vertical gene transfer) between parents and offspring.
Now scientists are turning more attention to horizontal gene transfer, the transfer of DNA rather than from parent to offspring, which tells us about the evolutionary mechanisms of other organisms, such as bacteria, and helps researchers better understand how antibiotic resistance is produced.
Photo Source: In the Monash University study, researchers found for the first time that horizontal gene transfer (HGT) may change the evolutionary rules of species; researcher McDonald says HGT is important for microbial evolution, especially for antibiotic-resistant evolution of human pathogens Antibiotic resistance genes are common in bacteria living in hospitals, sewers, and farms because of the trajectory of human activity, but when scientists tested for antibiotic-free environments, such as forests or estuaries, they were able to detect the presence of antibiotic-resistant genes.
Then the researchers conducted an evolutionary experiment to study how genes that induce antibiotic resistance spread in the environment, testing antibiotic-sensitive bacteria in antibiotic-free growth mediums, and allowing the bacteria being tested to get HGT from other antibiotic-resistant bacteria, before using genome-wide measurements. Sequencing techniques to confirm whether antibiotic-resistant genes spread in populations (even without a choice), while challenging evolving populations with high concentrations of antibiotics, it was found that groups receiving HGT were able to survive with antibiotic therapy, but not control bacterial groups that did not receive HGT.
Researchers have found that antibiotic-resistant genes may spread to groups that have not experienced antibiotic selection, and that although they are at low levels, they could provide new ideas and hope for later scientists to develop new antibiotics resistant to drug-resistant bacteria; the findings may help explain why antibiotic resistance in hospitals has evolved so rapidly.
this study, researchers explain for the first time how antibiotic-resistant genes remain in certain microbiomes, even if they are not under the pressure of antibiotic selection.
researchers say the study could also help explain why antibiotic-resistant bacteria persist for a long time after being treated with antibiotics, and why bacteria can rapidly develop antibiotic resistance even if they have not been exposed to antibiotics before.
The results of this paper are important because they explain how HGT changes the evolutionary rules of species, after previous studies have shown that the only genes that can spread in a population are those that can benefit from the current benefits (in the current environment experienced by a species) because natural selection removes lower-fit and harmful genes from the population.
Finally, researcher McDonald said that if HGT could transfer enough genes to a population, it might provide a force to stop natural selection and allow genes that do not benefit to spread through the population.
() Original source: Laura C. Woods, Rebecca J. Gorrell, Frank Taylor, et al. Horizontal gene transfer potentiates by reducing selective constraints on the spread of genetic variation, PNAS (2020) doi:10.1073/pnas.2005331117