'Primordial soup' rejected as life's start

LONDON, Feb. 15 (UPI) -- British and German scientists say life on Earth may have begun when energy from alkaline, deep-sea vents produced the lipids and proteins of the first cells.

The proposal comes from a multi-institution research team led by Nick Lane of University College London. The team's hypothesis rejects the theory proposed in 1929 by J.B.S Haldane that ultraviolet radiation converted the "primordial soup" of methane, ammonia and water into the organic compounds that later formed Earth's first cells. Critics of that theory argued UV radiation could not have been the source of the conversion, because it was not a sustainable energy source.

"Despite bioenergetic and thermodynamic failings, the 80-year-old concept of primordial soup remains central to mainstream thinking on the origin of life," said senior author William Martin of the Institute of Botany in Dusseldorf, Germany. "But soup has no capacity for producing the energy vital for life."

The team said it relied on the findings of NASA geochemist Michael Russell that alkaline deep-sea vents produce chemical gradients very similar to those used by nearly all living organisms today.

"Modern living cells have inherited the same size of proton gradient and, crucially, the same orientation -- positive outside and negative inside -- as the inorganic vesicles from which they arose," said study co-author John Allen of the University of London.

The research appears in the journal BioEssays.