New research rekindles secular origin of life debate

Secular scientists have differing viewpoints on what kick-started life on Earth. The first serious theory, put forth in the 1920s, proposed that a “primordial soup” of chemicals needed for life spontaneously assembled into simple living cells.

While no one has pinpointed the exact combination of chemicals that make up this primordial soup, researchers at Rutgers University and the City College of New York think they’ve identified one of the key components. In a paper published March 10 in Science Advances, they describe a chemical nicknamed “nickelback.” Using computer models and lab experiments, they constructed the chemical and tested its interactions with other substances. What they observed led them to conclude that the compound likely played a role in triggering the development of living cells.

But intelligent design experts disagree. Exposing false assumptions made in the paper, they argue that so-called  origin of life theories lack sufficient evidence.

Nickelback is a small peptide composed of 13 amino acids bound to two nickel ions. Peptides are the building blocks of proteins, which play a key role in the metabolic pathways needed to sustain life.

In designing nickelback, the researchers estimated that life originated on Earth 3.5 billion–3.8 billion years ago. Working under this assumption, the scientists reasoned that modern proteins are too complex to have existed billions of years ago. To discover these proteins’ primordial precursors, researchers reduced modern proteins known to be associated with metabolic processes to their most basic structures.

The scientists believe that Earth’s early oceans contained large amounts of nickel, which gives credence to the idea that nickel ions spontaneously bound to an existing peptide. They saw that once nickelback formed, the nickel ions could catalyze a reaction that produced hydrogen gas. Hydrogen gas can serve as an energy source to power cells’ metabolic processes.

“This work shows that not only are simple protein metabolic enzymes possible, but that they are very stable and very active—making them a plausible starting point for life,” Vikas Nanda, lead author of the paper and professor at Rutgers University, in a statement.

Brian Miller, research coordinator for the Center for Science and Culture at the Discovery Institute, explained how difficult it is for nickelback to form outside of a controlled laboratory. Nickelback contains five different amino acids. Chemical reactions that produce amino acids also generate, in higher proportions, an array of other molecules. The amino acids are more likely to chemically interact with these other molecules than with each other, making the generation of nickelback highly unlikely.

Even if nickelback could be generated, peptides can’t self-replicate. That means they are incapable of evolving into complex proteins in the absence of fully functional cells. All secular origin of life theories eventually run into this dilemma, Miller explained. Until an organism can self-replicate, it’s acted on purely by chemical and physical processes. In most circumstances, these processes break living molecules into simpler molecules. “So [at] any step in the origin of life, you’re having to do the opposite of what natural processes ever do,” said Miller.

Hugh Ross, astrophysicist and founder of the creation apologetics ministry Reasons to Believe, pointed out that a major flaw with origin of life theories is the timing. Ross said the earliest rocks showing signs of life are approximately 3.825 billion years old based on isotope dating. Isotopes are variations of a chemical element that are either lighter or heavier. The decay rate of an unstable isotope to a stable one, which is constant over time, can be used to calculate how old a substance is. Isotope evidence also indicates stable liquid water and stable rocks didn’t exist on Earth until 3.84 billion–3.83 billion years ago. This leaves too little time for chemistry to form life through naturalistic processes.

Ross noted that even some researchers most committed to a naturalistic explanation of life’s origins admit their models don’t work. Ross cited a 2019 Nature Communications commentary by Clemens Richert, a German origin of life researcher. In it, Richert called for scientists to be honest about the high level of human intervention in experiments performed to replicate prebiotic materials. Referring to this human intervention as the “Hand of God” dilemma, Richert admitted that the main agent that sparked life “will remain an enigma to many of us for the foreseeable future.”