Theoretical origin of life; without water (Introduction)

by David Turell , Saturday, May 23, 2015, 20:27 (3472 days ago) @ David Turell

One of the major problems in working with the protein molecules of life is that water tends to tear them apart. So starting on dry land!?:-http://www.newscientist.com/article/mg22229650.300-no-more-primal-soup-creating-life-without-water.html?page=1-"For Steven Benner, that is all a fairy tale. "We tend to think that water's properties are ideal for life, but the opposite is true," he says. "Water is corrosive." Benner is a chemist at the Westheimer Institute of Science and Technology in Gainesville, Florida, and for three decades he has been doing pioneering work in synthetic biology, which aims to recreate life's chemistry in the test tube. And he is no lone voice. As water's deleterious effects have become more apparent, many researchers are asking: is it time to dry out life's recipe?-"Life's molecules don't just dissolve in water; the electron-rich oxygen of its molecules attacks them, and they begin to fall apart. "In your body right now, the DNA in your cells is losing an amino group many times a second because of the action of water," says Benner. Living things keep their molecules intact only through clever chemical strategies that perpetually repair the breakages.-"Decades of research have shown that making nucleotides in water is a very tricky business. Individual steps can be made to work, but they don't all gel together. "We are still at the stage of scraping out the product of step seven, and carefully spooning it into the flask to begin step eight," says Benner. Fail to spoon in just the right amounts of various molecules at the right time, and the end result is a gunky mess.-***-"But he questions whether dry life arriving on a wet Earth on a Martian meteorite could have assimilated well. Genomic studies show that life on our planet traces back to a collection of cells that survived by sharing the products of their genes, creating a single-celled organism referred to as the last universal common ancestor. "If you dropped a primitive Martian cell into Earth's oceans, it is highly unlikely that it would have proliferated alone," he says. Rather, it would take a whole microbial ecosystem arriving, intact, from Mars.-"Or we tweak our story still further. Nicholas Hud, a chemist at the Georgia Institute of Technology in Atlanta, points out that most researchers accept that DNA somehow evolved from RNA, so we should at least consider the possibility that RNA evolved from a different molecule that was stable in water. "When I look at RNA, I see a molecule that is perfect at what it does, but that's hard to make," he says - perhaps a telltale sign that natural selection helped shape RNA. "Which is more probable? Life began on Mars, was transported to Earth and picked up where it left off, or life began on Earth, but with a molecule different from RNA?"-"Hud's thinking could remove the need for Kirschvink's Martian scenarios and Benner's chemistry, but would demand a rethink of the underlying assumption that life's chemical origin lies with RNA. It would seem fitting, though, that the ultimate solution to the water problem, even before life as we know it got started, could lie in the principles of natural selection. Stories about the origins of life begin and end with Darwin."-What does Darwin really have to do with it? Nothing.