Bacteria are fast evolving resistance to antibiotics, which is fast-tracking us to a future where our best drugs no longer work and simple infections become life-threatening once again. While new antibiotics are in the works, the bugs will eventually develop resistances to those too, so a longer term strategy might be to prevent them from evolving in the first place. A new study has found that bacteria use clever gambles to adapt – and showed how we could rig the game in our favor.
Instead, new research by McMaster behavioural scientists shows that in certain cases evolution works in the opposite direction, reversing individual improvements to benefit related members of the same group.
The research appears in the Journal of Evolutionary Biology, where lead author David Fisher shows that the increased evolution of selfless traits — such as sharing food and keeping watch for one another — is mathematically equivalent to the decreased evolution of individually beneficial traits.
“They’re two sides of the same coin,” Fisher explains. “On one side, traits evolve that benefit your kin, but don’t benefit you, because you’re helping your siblings or cousins. On the other side, traits that benefit you but cost your neighbours don’t evolve, because you’re causing damage to related individuals.”
An international group of researchers including biologists from the University of Maryland found that at least four species of marine ribbon worms independently evolved the ability to regrow a head after amputation.
Regeneration of amputated body parts is uncommon but does exist throughout the animal world—from salamanders, spiders and sea stars that can regrow appendages to a species of ribbon worm that can regenerate an entire individual from just a small sliver of tissue. But regenerative abilities were broadly assumed to be an ancient trait that some species managed to hold on to while most others lost through evolution.
This new study, which was published in the March 6, 2019 issue of Proceedings of the Royal Society B, turns that assumption on its head. In a survey of 35 species of marine ribbon worms, the researchers found that the ability to regenerate an entire head, including a brain, evolved relatively recently in four different species.
In the past few decades, a lethal disease has decimated populations of frogs and other amphibians worldwide, even driving some species to extinction. Yet other amphibians resisted the epidemic. Based on previous research, scientists at the INDICASAT AIP, Smithsonian and collaborating institutions knew that skin bacteria could be protecting the animals by producing fungi-fighting compounds. However, this time they decided to explore these as potential novel antifungal sources for the benefit of humans and amphibians.
“Amphibians inhabit humid places favoring the growth of fungi, coexisting with these and other microorganisms in their environment, some of which can be pathogenic,” said Smithsonian scientist Roberto Ibáñez, one of the authors of the study published in Scientific Reports. “As a result of evolution, amphibians are expected to possess chemical compounds that can inhibit the growth of pathogenic bacteria and fungi.”
The team first travelled to the Chiriquí highlands in Panama, where the chytrid fungus, responsible for the disease chytridiomycosis, has severely affected amphibian populations. They collected samples from seven frog species to find out what kind of skin bacteria they harbored.
In early times, the universe was an energetic mix of strongly interacting particles. The first particles to break free from this dense soup were neutrinos, the lightest and most weakly interacting particles of the Standard Model of particle physics. These neutrinos are still around us today, but are very hard to detect directly because they are so weakly interacting. An international team of cosmologists, including Daniel Baumann and Benjamin Wallisch from the University of Amsterdam, have now succeeded in measuring the influence of this ‘cosmic neutrino background’ on the way galaxies have become clustered during the evolution of the universe. The research was published in Nature Physics this week.
