Latency could preserve the ingredients of life on Earth

Jan. 8 () –

The chemical precursors of life faced the harsh conditions of the early Earth by reversible changes in activity and protectiona phenomenon known as latency.

This is suggested by new research published in Proceedings of the Royal Society B to elucidate how life emerged and persisted on a young planet Earth where asteroids pounded the surface, volcanoes spewed lava and carbon dioxide, and the thick, toxic atmosphere lacked oxygen.

Organisms use dormancy to mitigate the risk of death by protecting themselves from unfavorable conditions and resurrecting once favorable conditions return.

“If you are active, but there is no food because the river is drying up, for example, you are going to die,” he explains. in a statement Kevin Webste, associate scientist at the Planetary Science Institute (PSI) and author of the study. “But if you’re able to withstand those really dry conditions while you’re inactive, then you can get back to activity as soon as there’s water again and live to pass on your genetic information.”

Webster and his co-worker, Indiana University student Jay Lennon, dove into the fossil record and traversed the tree of life to discover that dormancy has been used by a wide variety of organisms throughout the history of life. Earth, including today.

“By decreasing mortality rates under suboptimal conditions, dormancy would reduce the probability of local and global extinction events. Furthermore, dormancy creates a ‘seed bank’ of inactive individuals,” the authors wrote, meaning that life does not need to restart repeatedly during Earth’s turbulent youth.

However, the key to this article is not only that latency made life more robust, but that Even before life arose, its chemical precursors probably exhibited traits of latency, including the ability to exist in different states of activity, to transition between these states of activity, and to experience some degree of protection from decay while dormant.

Some molecules, through various processes, can switch between a state of dormancy (during which they are protected, but cannot replicate) and activity (during which they are more vulnerable to the environment, but can replicate). The change between these states can occur in conjunction with changes in the environment, such as temperature or the availability of other molecules.

For example, DNA, a molecule that contains genetic information, is made up of two intertwined strands that can respond to changes in temperature. High temperatures can cause the two strands to separate and colder temperatures can cause two separated strands to spontaneously recombine. DNA can also wrap around proteins called histones to securely enclose its genetic code and then uncoil when there are favorable conditions for replication.

“We argue that these molecules can do these things in biological environments and that on the early Earth we might have had some of this behavior before the origin of life,” Webster said. In future work, Webster aims to test these ideas using models. Specifically, he wants to test how latency can affect the stability of chemical reaction networks. in prebiotic environments that undergo environmental changes.

Additionally, latency likely also influenced how life colonized the planet, depending on where it originated. For example, if life first flourished in an isolated inland hot spring, dormancy might have helped it disperse beyond the original oasis; If life developed in the ocean that spans the entire globe, then latency might not have played such a crucial role.

Understanding how life emerged, spread, and persisted on Earth can also shed light on how life might have originated elsewhere.

“How does life go from this purely non-living state to one that is finally alive?” That question fascinates me. because it can also guide the search for life on distant worlds,” Webster said. “It may tell us something about the processes a planet must go through for life to arise and what to look for once it arises.”