Researchers have proposed several competing theories for how life on Earth could have gotten its start, even before the first genes or living cells came to be. Despite differences between various proposed scenarios, one theme they all have in common is a network of molecules that have the ability to work together to jumpstart and speed up their own replication -- two necessary ingredients for life. However, many researchers find it hard to imagine how such a molecular network could have formed spontaneously -- with no precursors -- from the chemical environment of early Earth.

"Some say it's equivalent to a tornado blowing through a junkyard and assembling the random pieces of metal and plastic into a Boeing 747," said co-author Wim Hordijk, a visiting scientist at the National Evolutionary Synthesis Center in Durham, North Carolina, and a participant in an astrobiology meeting held there last year.

In a previous study published in 2004, Hordijk and colleague Mike Steel of the University of Canterbury in New Zealand used a mathematical model of simple chemical reactions to show that such networks might form more easily than many researchers thought. Indeed, biochemists have recently created such networks in the lab.