Yasemin Saplakoglu writes:

Scientists have debated why life became homochiral [that is, having molecular asymmetry], and whether it needed to happen or if it was purely a fluke. Were chiral preferences impressed on early life by biased samples of molecules arriving from space, or did they somehow evolve out of mixtures that started out as equal parts right- and left-handed?

“Scientists have been mystified by this observation,” said Soumitra Athavale, an assistant professor of organic chemistry at the University of California, Los Angeles. “They’ve come up with all sorts of proposals over the years, but it’s difficult to come up with proposals which are actually relevant geologically.” Moreover, while many theories could explain why one type of molecule might have become homochiral, none of them explained why whole networks of biomolecules did.

Recently, a group at Harvard University published a series of papers that present an intriguing solution for how life’s homochirality emerged. They suggest that magnetic surfaces on minerals in bodies of water on the primordial Earth, charged by the planet’s magnetic field, could have served as “chiral agents” that attracted some forms of molecules more than others, kicking off a process that amplified the chirality of biological molecules, from RNA precursors all the way to proteins and beyond. Their proposed mechanism would explain how a bias in the makeup of certain molecules could have cascaded outward to create a vast network of chiral chemistry supporting life. [Continue reading…]