Life might have Evolved in Clay, Researchers Find
Cornell University scientists might have unraveled the mystery around formation of life on earth. Their research suggests that clay supported the synthesis of biochemicals.
Dan Luo, of the Kavli Institute at Cornell for Nanoscale Science and team were looking for inexpensive hydrogels that could be used to produce proteins on a large-scale when they stumbled across the crucial evidence that could help solve one of the greatest mysteries in biology.
For centuries, humans have been speculating about the origins of life. Recently, a Texas Tech University researcher had presented a study describing the evolution of basic organisms, which suggested that key molecules came on earth from space and the planet provided the right conditions for them to jump-start life. However, nobody has been able to explain how inorganic molecules suddenly got together to form complex life.
In the present study, scientists speculate that clay hydrogels provided a platform for chemicals to come together and form complex biomolecules.
"We propose that in early geological history clay hydrogel provided a confinement function for biomolecules and biochemical reactions," said Luo, according to a news release.
Experiments using water samples that resemble ancient seawater have shown that clay forms a hydrogel under certain conditions. Hydrogel is a network of polymer chains that has the ability to soak-up huge quantities of water. Basically, these gels are super-sponges. Over billions of years, the trapped chemicals reacted and formed biochemicals such as proteins and DNA.
Researchers said that these gels protected the cells until they developed their own membranes. Previously, other studies had assumed that fat bubbles acted as precursors for cell membranes.
Hydrogels are currently being studied extensively in tissue engineering. These gels are extremely flexible, almost like natural tissues, which make it an ideal tissue growth supporter.
The study is available in the Nov. 7 online issue of the journal Scientific Reports. Read it here.
Other candidates that claim to be cradle of life
Previous research has shown that pumice- the porous volcanic rock- might have provided the best place for inorganic molecules to combine. This hypothesis was proposed by Martin Brasier, Richard Matthewman, and Sean McMahon, University of Oxford (U.K.).
However, Jack Szostak, winner of the Nobel Prize in Medicine in 2009, countered the theory stating that the environment a pumice rock provided was too simple for the initiation of life, reports USA Today.
"I think a more complex and diverse environment might be necessary - both chemically and physically. Ponds or lakes in a geothermal active region seem more reasonable to me," he added.
Clay, according to the researchers, appeared just at the time biomolecules began to develop into primitive cells. The team is now trying to find practical applications of hydrogels and understand its role in cell evolution.