Cosmic Rays may have Left Indelible Imprint on Early Life, Stanford Physicist Says

martyb writes:

Cosmic Rays May Have Left Indelible Imprint On Early Life, Stanford Physicist Says:

Chirality, also known as handedness, is the existence of mirror-image versions of molecules. Like the left and right hand, two chiral forms of a single molecule reflect each other in shape but don't line up if stacked. In every major biomolecule - amino acids, DNA, RNA - life only uses one form of molecular handedness. If the mirror version of a molecule is substituted for the regular version within a biological system, the system will often malfunction or stop functioning entirely. In the case of DNA, a single wrong handed sugar would disrupt the stable helical structure of the molecule.

Louis Pasteur first discovered this biological homochirality in 1848. Since then, scientists have debated whether the handedness of life was driven by random chance or some unknown deterministic influence. Pasteur hypothesized that, if life is asymmetric, then it may be due to an asymmetry in the fundamental interactions of physics that exist throughout the cosmos.

"We propose that the biological handedness we witness now on Earth is due to evolution amidst magnetically polarized radiation, where a tiny difference in the mutation rate may have promoted the evolution of DNA-based life, rather than its mirror image," said Noemie Globus lead author of the paper and a former Koret Fellow at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).

In their paper, published on May 20 in Astrophysical Journal Letters, the researchers detail their argument in favor of cosmic rays as the origin of homochirality.

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