Did Earth’s Genetic Raw Materials Arrive From Extraterrestrial Sources?

According to a report from a European and American collaborative group of scientists interested in Earth and Planetary science, analysis of a meteorite suggests that organic compounds involved in the chemical reactions that produce the purines and pyrimidines that make up DNA and RNA may have already been present in the early solar system, reaching Earth through meteor bombardments and other contacts with extraterrestrial sources. The abstract of the article by astrobiologist Zita Martin and colleagues, reads as follows:

"Carbon-rich meteorites, carbonaceous chondrites, contain many biologically relevant organic molecules and delivered prebiotic material to the young Earth. We present compound-specific carbon isotope data indicating that measured purine and pyrimidine compounds are indigenous components of the Murchison meteorite. Carbon isotope ratios for uracil and xanthine of δ13C=+44.5‰ and +37.7‰, respectively, indicate a non-terrestrial origin for these compounds. These new results demonstrate that organic compounds, which are components of the genetic code in modern biochemistry, were already present in the early solar system and may have played a key role in life's origin."

See: Martins Z, Botta O, Fogel ML et al. Extraterrestrial nucleobases in the Murchison meteorite. Earth and Planetary Science Letters 2008;270:130-6.

http://www.sciencedirect.com/science/article/B6V61-4S3G406-1/1/eb630b2a66119aa41767b7be4b697c44

Speaking of Life

To see life, look here:

http://en.citizendium.org/wiki/Life

Citizendium's latest version of its answer to the perennial question:

What is life?

Many other interesting free encyclopedia articles at Citizendium:

http://en.citizendium.org

The Ride of Life

News from the Cardiff Centre for Astrobiology

The Earth moves in many different patterns concurrently. It rotates on an axis, it wobbles its rotation on that axis, it revolves around the sun, it moves with the sun and its system of planets through space in the Milky Way galaxy, and moves with the galaxy's spinning and hurtling away from some and toward other galaxies.

In addition to those patterns, along with the solar system, the Earth bounces alternating bi-directionally through the plane of the galaxy. The denser parts of the galaxy's plane has huge gravitational masses that dislodge comets from their paths, some of which impact Earth. The bounce-throughs occur every 35-40 million years, in keeping with Earth's 36 million year interval of increased comet impacts. Several of Earth's mass extinctions coincide, too.

The researchers who "discovered", in a computational simulation, the bouncing solar system ride, speculate that the bombardments might strew some of Earth's microorganisms through the galaxy, perhaps seeding life elsewhere. Or introducing new life. Perhaps other solar systems do likewise. Imagine, a galactic-wide primordial soup! An alphabet soup spelling 'mother'.

See story at:

http://www.cardiff.ac.uk/news/articles/did-the-solar-system-bounce-finish-the-dinosaurs.html

Did the solar system 'bounce' finish the dinosaurs?

Designer Evolution

Suppose you wanted to direct the evolution of molecular systems that behaved according to parameters you set. By whatever means you implement that, you must have a method for directing evolution of individual molecules toward desired functional properties, since the system must have the appropriate parts to generate its functionality. In that case, you must have a molecule generating factory for the component parts. Starting with enormous numbers of generators of different efficiency/capacity, and limiting the substrate precursors of the desired molecules, iteratively in rapid succession, and imposing the parameters defining the desired functional molecule, natural selection will favor preservation of the high-capacity, fast-reacting, efficient generators that yield the targeted molecule.

 

That process admits of automation on a chip, as demonstrated by Brian M. Paegel and Gerald F. Joyce, in the Departments of Chemistry and Molecular Biology, of the Scripps Research Institute, La Jolla, California, and in the Skaggs Institute for Chemical Biology, of the Scripps Research Institute, La Jolla, California, both in the U.S.

 

The procedure produces a continuous stream of real-time data, giving the experimenter a record of the evolutionary course in terms of population size and heterogeneity, and growth conditions, including availability of limiting resources. Each microchip contains multiple microfluidic circuits independently addressable. The method costs modestly, so the process makes Darwinian evolution readily accessable. As easy almost as implementing the evolution of the system on a computer.

 

Darwinian Evolution on a Chip. Paegel BM, Joyce GF. PLoS Biology Vol. 6, No. 4, e85 doi:10.1371/journal.pbio.0060085

Chip-Based Designer Molecular Evolution

Suppose you wanted to direct the evolution of molecular systems that behaved according to parameters you set. By whatever means you implement that, you must have a method for directing evolution of individual molecules toward desired functional properties, since the system must have the appropriate parts to generate its functionality. In that case, you must have a molecule generating factory for the component parts. Starting with enormous numbers of generators of different efficiency/capacity, and limiting the substrate precursors of the desired molecules, iteratively in rapid succession, and imposing the parameters defining the desired functional molecule, natural selection will favor preservation of the high-capacity, fast-reacting, efficient generators that yield the targeted molecule.

 

That process admits of automation on a chip, as demonstrated by Brian M. Paegel and Gerald F. Joyce, in the Departments of Chemistry and Molecular Biology, of the Scripps Research Institute, La Jolla, California, and in the Skaggs Institute for Chemical Biology, of the Scripps Research Institute, La Jolla, California, both in the U.S.

 

The procedure produces a continuous stream of real-time data, giving the experimenter a record of the evolutionary course in terms of population size and heterogeneity, and growth conditions, including availability of limiting resources. Each microchip contains multiple microfluidic circuits independently addressable. The method costs modestly, so the process makes Darwinian evolution readily accessible. As easy almost as implementing the evolution of the system on a computer.

Darwinian Evolution on a Chip. Paegel BM, Joyce GF. PLoS Biology Vol. 6, No. 4, e85 doi:10.1371/journal.pbio.0060085