While many armchair philosophers are searching for the meaning of life, researchers are hard at work investigating the origins of life on Earth. New findings suggest that a lump of clay could have provided a platform for the formation of primordial cells.
Previous research indicated that chemicals found in so-called montmorillonite clay could catalyze reactions involved in constructing RNA from nucleotides. Martin M. Hanczyc, Shelly M. Fujikawa and Jack W. Szostak of Massachusetts General Hospital determined that the clay could also encourage fatty acids to form small fluid-filled sacs known as vesicles. Indeed, vesicles developed 100 times faster in the presence of clay than they did without it, suggesting that clay could have "greatly facilitated the emergence of the first cells," the authors write in today's issue of the journal Science. (In the image above, the red indicates RNA that is attached to clay particles encapsulated within a vesicle.) Once forged, the vesicles grew by incorporating additional fatty acids. The scientists also caused the sacs to divide by forcing them through small pores, a process that the vesicles survived without losing their contents.
"Now that we have a proof-of-principle that growth and division is possible in a purely physical-chemical system, we are working on a way to get this cycle to function in a way that is more natural," Szostak notes. "Clearly, there are a lot of complicated and interesting processes going on here, and how this pathway leads to biological systems is not at all straightforward."