New models reveal the genesis of life

By Linksey Valich

February 11

About four billion years ago, the earliest traces of life in the form of microorganisms appeared on Earth. It is obvious that the advent of life is tightly linked with the chemical and physical properties of early Earth, even if scientists are still trying to pinpoint exactly when and how these bacteria first formed.

According to Dustin Trail, an associate professor of earth and environmental sciences at the University of Rochester, "It seems plausible to suppose that life could have originated differently—or not at all."

But what did Earth look like billions of years ago, and what features would have aided the emergence of life? Key details in the investigation are revealed in a report written by Trail and Thomas McCollom, a research associate at the University of Colorado Boulder. The study has significant ramifications for both the study of the beginnings of life and the hunt for extraterrestrial life.

We are in an exciting period where humanity is looking for life in other planetary systems and on other planets and moons, according to Trail. "However, we are still unsure of how or even when life on Earth first began. Our work, which identifies particular circumstances and chemical pathways that may have enabled the development of life, will undoubtedly play a significant role in the hunt for life beyond Earth."

Metals' significance in the origin of life

Proteomics, the study of proteins, genomics, the study of genes and their functions, and metallomics, an emerging field that investigates the significant role of metals in carrying out cellular functions, are just a few of the disciplines that are typically used in research into life and its origins. Trail and McCollom sought to know what metals would have been present when bacteria first emerged billions of years ago because the needs for particular metals altered as life evolved.

Because there haven't been any studies that provide geologically solid constraints on metal concentrations of fluids for the earliest periods of Earth's history, Trail says, "scientists have generally assumed all metals were available when hypotheses are proposed for different origin-of-life scenarios."

To address this shortcoming, Trail and McCollom studied the composition and characteristics of fluids in the lithosphere—the outer layer of Earth that includes the crust and upper mantle—billions of years ago. These lithospheric fluids are key pathways to transport dissolved parts of rocks and minerals between Earth's interior and hydrothermal pools in its exterior where microbial life could have formed. While researchers cannot directly measure the metals that existed billions of years ago, by determining the properties of the fluids, they can infer what metals—and the concentrations of the metals—could feasibly have been transported between Earth's interior and exterior during the time when life emerged on the planet.

minerals with a billion-year age hold clues

Often, the only direct sources of knowledge about Earth's early past are rocks and minerals that are billions of years old. This is due to the fact that when they form, rocks and minerals preserve information about the make-up of the Earth.

Manganese was one metal they tested that might have been present in significant proportions. Manganese

aids enzymes in the breakdown of cholesterol and carbohydrates and helps the body produce bones, yet it is rarely taken into account in theories about the origin of life.

According to Trail's research, metals like manganese may serve as vital connections between the "solid" Earth and developing biological systems on the planet's surface.

According to Trail, the findings will assist scientists who are researching the origin of life by giving their tests and models more precise data.

The origin of life will be better understood through experiments created with this knowledge in mind.