Scientists Unravel Mystery of Life’s Origins on Earth and Beyond
Scientists have pinpointed how a cocktail of specific amino acids informed the genetic code of every single lifeform on Earth, providing a glimpse into the mystery of how life arose out of non-living matter. The findings, published in the Journal of the American Chemical Society, suggest that natural selection may have played a role before life itself even existed on our planet.
A team from Johns Hopkins University and Charles University used the NASA Jet Propulsion Laboratory’s Origins and Habitability Lab to recreate the primordial soup of early Earth, which included a mix of amino acids that were abundant before life ever appeared. It is believed that some of these were produced when UV light from the Sun interacted with gases in the atmosphere of the time, while others arrived aboard meteorites that impacted the planet more often than they do now.
The team discovered that ancient organic compounds integrated the amino acids best suited for protein folding into their biochemistry, suggesting that life emerged and thrived on Earth not only because some amino acids were available in ancient environments, but mainly because some of them were particularly efficient in helping proteins adopt specific shapes to perform crucial functions.
“Protein folding was basically allowing us to do evolution before there was even life on our planet. You could have evolution before you had biology, you could have natural selection for the chemicals that are useful for life even before there was DNA,” said Stephen Fried, co-lead author of the study.
This research has implications for the possibility of finding life beyond Earth. Fried believes that many of the canonical amino acids arrived from space, suggesting that such compounds may be abundant in other parts of the universe, possibly giving rise to life there too.
At JPL, the team also simulated the chemistry of early Earth and carried out a key chemical reaction involved in metabolism, the process living organisms use to convert fuel (such as sunlight or food) into energy. They plan to continue trying to simulate each step in the metabolism process, hoping to find a step that can only occur inside a protective membrane. Finding this could help scientists narrow down when membranes became necessary in the emergence of life and provide a glimpse back in time.
The study of the origins of life is an ongoing process, but the research conducted by the team at JPL could help us better understand our own planet and potentially others. As JPL research scientist Laurie Barge says, “science is all about repetition.
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