New formulas for the origin of life could pave the way for distant planets to be inhabited

Life on a distant planet, if it exists, may not resemble life on Earth. But there are only a limited number of chemical ingredients in the universe’s pantry, and there are few ways to mix them. A team led by scientists at the University of Wisconsin-Madison exploited these limitations to write a cookbook containing hundreds of chemical formulas that could create life.

Their ingredient list may focus on the search for life elsewhere in the universe by highlighting the most likely conditions (planetary versions of mixing techniques, heat oven temperature and cooking time) to develop recipes.

According to researchers, the progression from basic chemical constituents to the complex cycles of metabolism and cell reproduction that define life requires more than simple beginnings but also requires repetition.“The origin of life is really a process from nothing,” said Betül Kaçar, a NASA-supported astrobiologist and professor of bacteriology at UW-Madison. “But that can’t happen just once. Life depends on chemistry and conditions that can create a self-reproducing reaction pattern.”

Chemical reactions that produce molecules that encourage the same reaction to occur repeatedly are called autocatalytic reactions. In a new study published in the Journal of the American Chemical Society, Zhen Peng, a postdoctoral researcher in the Kaçar lab, and his collaborators compiled 270 molecular combinations , involving atoms from all groups and series of the periodic table, with the possibility of lasting effects. self-catalysis.

“It was thought that these sorts of reactions are very rare,” says Kaçar. “We are showing that it’s actually far from rare. You just need to look in the right place.”

Researchers focus their studies on what is called proportional response. In these reactions, two compounds consisting of the same element with a different number of electrons, or reactive states, combine to create a new compound in which the element is in the middle of its original reactive state.

To be autocatalytic, the reaction outcome must also provide raw materials for the reaction to occur again, so the outcome becomes the new input, said study co-author Zach Adam and geologist at UW-Madison who studies the origins of life on Earth, explains. Earth. Rate reactions produce many copies of some of the molecules involved, thus providing raw materials for the subsequent autocatalytic steps.

“If these conditions are met, you can start with relatively few of these outcomes,” Adam says.“Each time you do a cycle, you release at least one more product, which speeds up the reaction and makes it even faster.”

The autocatalytic mechanism is like an increasing number of rabbits. Pairs of rabbits combine, giving birth to new litters of rabbits, then the newly grown rabbits will pair up and form more rabbits. It doesn’t take a lot of rabbits to have more rabbits soon.

However, searching the universe for floppy ears and fuzzy tails is probably not a winning strategy.Instead, Kaçar hopes chemists will extract ideas from the new study’s recipe list and test them in pots and pans that simulate alien kitchens.

“We will never know for sure exactly what happened on this planet to create life. We don’t have a time machine,” Kaçar said. “However, in vitro, we can create a variety of planetary conditions to understand how the dynamics needed to sustain life could have evolved in the first place.”

Kaçar leads a NASA-backed corporation called MUSE, which specializes in the use and selection of metals across the ages.Her lab will focus on reactions involving the elements molybdenum and iron, and she’s excited to see what others cook up from the more exotic and unusual sections of the new cookbook.

“Carl Sagan said that if you want to make a cake out of nothing, you must first create the universe,” Kaçar said. “I think if we want to understand the universe, we need to bake some pies first.”