Nav: Home

New genes out of nothing

June 04, 2019

One key question in evolutionary biology is how novel genes arise and develop. Swedish researchers now show how new genes and functions that are advantageous to bacteria can be selected from random DNA sequences. The results are presented in the scientific journal mBio.

How do new genes and functional proteins arise and develop? This is one of the most fundamental issues in evolutionary biology. Two different types of mechanism have been proposed: (1) new genes with novel functions arise from existing genes, and (2) new genes and proteins evolve from random DNA sequences with no similarity to existing genes and proteins. In the present study, the researchers explored the latter type of mechanism: evolution of new genes and proteins from randomised DNA sequences - de novo evolution, as it is called. It is fairly easy to understand that when a gene already exists, it can be modified and acquire a new function. But how does "nothing" turn into a function affording a small advantage that is favoured by natural selection?

The raw material for the experiment was an big library of some 500 million randomised gene sequences, from which peptide sequences with a biological function were identified. In the experiment, random gene sequences were placed on a plasmid and overexpressed. The scientists then investigated whether they could give bacteria a specific, defined property. Were they, for example, able to give the bacteria antibiotic resistance? They identified several short peptides (22-25 amino acids long) that could give the bacteria a high degree of resistance to aminoglycosides, an important class of antibiotics used for severe infections.

"When the project started, we had low expectations. We were amazed when we found peptides able to confer a resistance level 48 times higher," says Dr Michael Knopp, the study's lead author.

Through a combination of genetic and functional experiments, the scientists were able to demonstrate that the peptides cause resistance by attaching themselves to bacterial cell membranes and affecting the proton potential across the membrane. The disruption of the proton potential causes a decrease in antibiotic uptake, rendering the bacteria resistant.

"This study is important because it shows that completely random sequences of amino acids can give rise to new, advantageous functions, and that this process of de novo evolution can be studied experimentally in the laboratory," says Dan I. Andersson, Professor of Medical Bacteriology, who is chiefly responsible for the study.
-end-


Uppsala University

Related Bacteria Articles:

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.