Life's First Spark Re-Created in the Laboratory

source: http://richarddawkins.net/article,3845,n,n

http://www.wired.com/wiredscience/2009/05/ribonucleotides/

A fundamental but elusive step in the early evolution of life on Earth has been replicated in a laboratory.

Researchers synthesized the basic ingredients of RNA, a molecule from which the simplest self-replicating structures are made. Until now, they couldn’t explain how these ingredients might have formed.

“It’s like molecular choreography, where the molecules choreograph their own behavior,” said organic chemist John Sutherland of the University of Manchester, co-author of a study in Nature Wednesday.

RNA is now found in living cells, where it carries information between genes and protein-manufacturing cellular components. Scientists think RNA existed early in Earth’s history, providing a necessary intermediate platform between pre-biotic chemicals and DNA, its double-stranded, more-stable descendant.

Continue reading:
http://www.wired.com/wiredscience/2009/05/ribonucleotides/

Also see:
RNA world easier to make - Nature
Molecule of life emerges from laboratory slime - New Scientist
HOW RNA GOT STARTED - Science News
Found: the origin of life - The Independent
Chemist Shows How RNA Can Be the Starting Point for Life - NY Times

Inspirational Orbits - Astronomers are finding new planets

source: Scientific American, June 2009 by John Rennie, Editor-in-Chief

The year 1609 was noteworthy for two astronomical milestones. That was when Galileo built his first telescopes and began his meticulous study of the skies. Within months he discovered the four major satellites of Jupiter, saw that Venus (like our moon) has illuminated phases and confirmed earlier observations of sunspots—all evidence that undermined the Aristotelian model of an unchanging, Earth-centered cosmos.

During that same year, Johannes Kepler published Astronomia Nova, which contained his detailed calculation of the orbit of Mars. It also established the first two laws of planetary motion: that planets follow elliptical orbits, with the sun at one focus, and that planets sweep through equal areas of their orbits in a given interval.

Small wonder, then, that when the United Nations General Assembly declared an International Year of Astronomy to promote the wider appreciation of the science, it selected 2009, the quadricentennial of those standout accomplishments (among many) by Galileo and Kepler that informally founded modern astronomy.

Currently astronomers can look beyond the familiar planets and moons to entirely new systems of worlds around other stars. As I write this, the tally stands at 344 known extrasolar planets. Only a handful of these bodies were found by telescopic means that Galileo or Kepler would have recognized, but each one owes its discovery to their work. A recent and surprising trend is the apparent abundance of planets turning up close to very small stars—suns that may not be much larger than the planets circling them.

Astronomers Michael W. Werner and Michael A. Jura have more in their article starting on page 26, including why the existence of these unlikely planetary systems might imply that the universe is chockfull of planets.

New, improved recipe cooks up life molecule

• 13 May 2009 by Kate Ravilious
• Magazine issue 2708. Subscribe and get 4 free issues.

CREATING life in the primordial soup may have been easier than we thought. Two essential elements of RNA have finally been made from scratch, under conditions similar to those that likely prevailed during the dawn of life.

The question of how a molecule capable of storing genetic information - even DNA's simpler cousin RNA - could ever have arisen spontaneously in the primordial cooking pot has perplexed scientists for decades. RNA consists of a long chain composed of four different types of ribonucleotides, which each consist of a nitrogenous base, a sugar and a phosphate.

Most people assumed that these three components first formed separately, and then combined to make the ribonucleotides. The only trouble was that it seemed impossible that two of the four bases with particularly unwieldy chemistry ever reacted spontaneously with the sugar.

To tackle this problem, John Sutherland from the University of Manchester, UK, tried to work out a new recipe for RNA that gets by without forcing isolated bases and sugar molecules to react. His team experimented by cooking up ribonucleotides from five small molecules thought to be present in the primordial soup. "We started with the same building blocks as others, but take a different route," Sutherland says.

And this time the cooks seem to have got it right. The recipe and conditions that they came up with to mix the five ingredients - including a good blast of UV light - produce ribonucleotides via a joint precursor molecule that contains both the base and the sugar instead of making each in their free form (Nature, DOI: 10.1038/nature08013).

This package deal sidesteps the problem of getting two unwilling partners to react, but only thanks to another trick, say the researchers. The reaction worked only when phosphate was present right from the start, although it does not react with the mixture until near the final stages. It turns out it is needed as a catalyst and as a chemical buffer early on.

"We don't use any way-out scenarios - all the conditions are consistent with what we know about early Earth," says Sutherland. William Scott, from the University of California in Santa Cruz agrees: "It's a great leap forward that demonstrates how prebiotic RNA molecules may have assembled spontaneously from simple and presumably relatively abundant constituents."

It's a great leap forward that demonstrates how prebiotic RNA molecules may have assembled

The need for UV light suggests life didn't begin in a submarine vent, one possible scenario. Instead, it points towards a warm pond - an idea first mooted by Charles Darwin, who knew nothing of RNA.