Nav: Home

Chemical evolution -- One-pot wonder

October 09, 2019

Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth - under the same environmental conditions.

Evolution has a history: Before life could be formed on the then still young planet, the first simple building blocks must have been created some four billion years ago that set its formation in motion. Under what conditions and in what ways did such molecules come together to form more complex genetic polymers that were able to replicate themselves - precursors of today's DNA? Scientists around Professor Thomas Carell at the Ludwigs-Maximilian-Universitaet (LMU) Munich, are now able to explain another, if not the decisive, step in this chemical evolution that preceded biological phylogeny. They report about it in the renowned journal Science.

In their new work, Thomas Carell and his team propose a cascade of chemical reactions in which the four different components of the hereditary molecule RNA can all be produced under identical early Earth conditions: the primordial soup - cooked in one pot, so to speak. So far, there have been two competing pathways that required different geochemical settings on early Earth. One leads to the construction of the so-called pyrimidines, the letters C (cytosine) and U (uracil) in the RNA alphabet, the other to A (adenine) and G (guanin), the purines. Carell's team had already described the reaction path to the latter molecules in a previous paper. Now the Munich scientists have finally created all four genetic building blocks that might have jump-started life.

Accordingly, the simplest chemical ingredients and reaction conditions, such as those found on Earth millions of years ago on geothermal fields with subsoil volcanic activity or in shallow ponds for example, were sufficient to keep the synthesis of the RNA building blocks, going over a whole series of reaction steps. Starting materials for the experiments, which were intended to simulate prebiotic conditions, were substances as simple as ammonia, urea and formic acid. It also needed salts such as nitrites and carbonates as well as metals such as iron and zinc, which are present in large quantities in the Earth's crust. The chain of chemical reactions was driven only by wet-dry cycles, such as those caused by hydrothermal sources or periods of drought or rain.

Thomas Carell calls it a "breakthrough." It is interesting to see how comparatively homogeneous the reaction conditions are for the individual steps of synthesis. Even small fluctuations of physical parameters such as mild warming or cooling or the change between a slightly acidic and a slightly alkaline reaction environment are sufficient. "There are few complex molecules that can be produced in such narrow reaction bands," says the LMU chemist. Such simple framework conditions, he concludes, made it all the more plausible that these reaction cascades and thus a decisive step in chemical evolution could have taken place on early Earth.

Science 2019
-end-


Ludwig-Maximilians-Universität München

Related Evolution Articles:

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.
Evolution of aesthetic dentistry
One of the main goals of dental treatment is to mimic teeth and design smiles in the most natural and aesthetic manner, based on the individual and specific needs of the patient.
An evolution in the understanding of evolution
In an open-source research paper, a UVA Engineering professor and her former Ph.D. student share a new, more accurate method for modeling evolutionary change.
Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
Tracing the evolution of vision
The function of the visual photopigment rhodopsin and its action in the retina to facilitate vision is well understood.
Directed evolution comes to plants
Accelerating plant evolution with CRISPR paves the way for breeders to engineer new crop varieties.
More Evolution News and Evolution Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.