Water-Filled Micropores in Rock May Have Acted as the 'Wombs' for Life on Ancient Earth

Water-filled micropores in hot rock may have been the nurseries in which life on Earth began. Scientists have found that the temperature gradients in these pore systems actually promote the cyclical replication and emergence of nucleic acids.

Scientists have long wondered in what habitats on Earth promoted the emergence of the first life-forms. One precondition for the origin of life is that comparatively simple biomolecules must have opportunities to form more complex structures, which were capable of reproducing themselves.

In the early oceans, these biological compounds would have been presents in tiny concentrations. Now, though, researchers may have discovered the necessary conditions for the production of life. They've shown experimentally that pore systems on the seafloor that were heated by volcanic activity could have served as a type of prehistoric "womb" for life.

"The key requirement is that the heat source be localized on one side of the elongated pore, so that the water on that side is significantly warmer than on the other," said Dieter Braun, one of the researchers, in a news release.

Preformed molecules that are washed into the pore are trapped with the heat, and then concentrated by the action of the temperature gradient. By trapping these molecules, the pores can satisfying a major condition for the formation of life.

"We used tiny glass capillary tubes to construct an analog of the natural pores found in rock, heated the pore from one side and allowed water containing dissolved fragments of linear DNA of varying lengths to percolate through it," said Braun. "Under such conditions, the long strands are indeed trapped within the pore. Pores that were exposed to heat are frequently found in igneous rock formations, and they were certainly common in rocks of volcanic origin on the early Earth. So this scenario is quite realistic. And the temperature effect is enhanced by the presence of metal inclusions within the rock, which conduct heat at rates 100 times higher than water."

The findings reveal a possible way that life may have first emerged on our planet. This, in turn, tells scientists a bit more about where to look for life on other planets.

The findings are published in the journal Nature Chemistry.

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