Biology

Scientists offer solution for chemical chicken-and-egg problem of the origins of life

Scientists offer solution for ...
Researchers have shown how life may have arisen from non-living matter in the "primordial soup" of early Earth, thanks to molecules released during volcanism
Researchers have shown how life may have arisen from non-living matter in the "primordial soup" of early Earth, thanks to molecules released during volcanism
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Researchers have shown how life may have arisen from non-living matter in the "primordial soup" of early Earth, thanks to molecules released during volcanism
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Researchers have shown how life may have arisen from non-living matter in the "primordial soup" of early Earth, thanks to molecules released during volcanism

How life arose from non-living material is one of the most profound mysteries facing science, and now a new study from the University College London (UCL) may have brought us a step closer to understanding it. The team may have solved a long-standing chicken-and-egg riddle related to how different types of peptides and proteins interact to give rise to life.

Evolution can only be traced back so far – at a certain point we have to wonder how life sparked out of lifeless matter. It's generally thought that everything started with a "primordial soup" rich in nutrients, which pooled on the surface or surrounded deep-sea hydrothermal vents. Energy from lightning strikes or volcanic activity can kickstart the process, allowing amino acids to link up, forming peptides that can go on to form proteins and eventually life.

But as the researchers on the new study point out, there's a problem with that story.

"Peptides, which are chains of amino acids, are an absolutely essential element of all life on Earth," says Matthew Powner, lead author of the study. "They form the fabric of proteins, which serve as catalysts for biological processes, but they themselves require enzymes to control their formation from amino acids. So we've had a classic chicken-and-egg problem – how were the first enzymes made?"

To get to the bottom of the conundrum, the researchers ignored amino acids for a moment and focused on their precursors – molecules called aminonitriles. Normally, these molecules begin stacking into amino acids only in either strongly acidic or alkaline environments, and then the amino acids need energy to make peptides.

But the team found that they could skip both of those steps, turning aminonitriles directly into peptides. The process worked in water by combining aminonitriles with hydrogen sulfide and ferricyanide. These two molecules are outgassed by volcanoes, meaning they would likely have been around on early Earth.

"This is the first time that peptides have been convincingly shown to form without using amino acids in water, using relatively gentle conditions likely to be available on the primitive Earth," says Saidul Islam, co-author of the study.

Along with helping us better understand how life arose, the researchers say the technique could be applied to synthetic chemistry, making for more efficient ways to produce materials and pharmaceuticals. The next steps for the team are to investigate other ways to turn aminonitriles into peptides.

The research was published in the journal Nature.

Source: University College London via Science Daily

11 comments
deng
There are two distinct energy...life and matter, using material instrument to see life, is not possible, since life energy cannot be perceived by dead matter. Life can only be observe by us (life) in the presence of matter thru Its characteristics, like awareness, growth, desires and will... otherwise matter without the presence of life, it is just a dead matter. In the second law of thermodynamic, matter molecular structures become complex when life is present and become simple after life has gone. This is why scientist cannot replicate life in the laboratory using chemicals, simple because life is distinct energy from matter. On side note: This is also the reason why people cannot be happy with material things.
TerenceKuch
Since early conditions in our solar system would not be unique, or even highly unusual, among other systems in the galaxy, it's very probable that this biochemical mechanism has been at work in many other solar systems - life therefore is likely to be widespread. I don't know if this is something to cheer about or not. Two cheers, maybe.
dfmd
The chicken/egg conundrum is a linear thinking trap. Correct answer: Neither came first. They are phase states of the same thing. The citric acid cycle is constantly eating its tail and can also run backwards. Life is a recursive algorithm. Read "Goedel, Escher, Bach An Eternal Golden Braid" and learn to dance on Indra's Net to a Beatles tune.
Username
@deng: Energy is the capacity to do work. Life is just chemical reactions. However rainbows and lollipops make most people happy.
bwana4swahili
Based on this article scientists still have a LONG LONG way to go before spontaneously creating life from chemical elements! My bet for life on Earth is still panspermia.
Douglas E Knapp
bwana4swahili, Panspermia just pushes the problem to another world but the chemicals will be the same but perhaps with a different ratio and perhaps other temperatures and radiation levels, still same problem. This research is almost as relavast on another world as it would be on ours. Life started somewhere and it likely started on a world a lot like ours was.
Douglas Bennett Rogers
There is nothing wrong with chemical evolution of chemicals. The problem is with consciousness arising from this. There is nothing wrong with starting with essential consciousness and having everything arise from this. After some examination this makes a lot more sense.
Signguy
Typical human logic; my experience has come to one great conclusion: there is a God who has created life because he is God and he can do that. In "Christianity" one meets The giver of Life Jesus; then, because he speaks and acts in our lives, proving beyond any doubt that he exists, the thought becomes reality.
GordonHoffman
What are the odds that the chemicals could form a complex life, and then to form compatable lives that could sexually reproduce? Especially when one species would have to add an additional Gene set at the exact same time as another. It doesn't seem probable - the results would have to have been manipulated by some one or some thing. My guess is that the egg came first.
christopher
Just because we exist, doesn't mean other life does, did, or will: I am amazed nobody does the math - it doesn't seem that hard. You need the right temperature, right magnetic effects to keep out the bad stuff, and the right chemical ingredients with the right mixing conditions - then it's simply a probability thing. We know how big atoms and universes are now, we can calculate the probability of those conditions. So - do we exist because the earth produced just enough random combinations of atoms bumping into each other under our ideal conditions... or... because the universe did?