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Origin & Evolution of Life: October 2008


Researchers from NAI's University of Arizona team and their colleagues at the University of Leeds have a new paper in Angewandte Chemie International Edition dealing with prebiotic chemistry and the early Earth. Working both experimentally and with models of the early atmosphere, the team shows that the Hadean and early Archaean Earth was primed with an abundance of condensed phosphates, enabling the formation of the necessary precursors of RNA and DNA. This research removes one of the large stumbling blocks in prebiotic chemistry- that the early Earth lacked a low-temperature reservoir of activated phosphate compounds capable of eventually leading to the origin of life.

Source: NAI Newsletter

Members of NAI's Penn State, Carnegie Institution, and MIT teams report in a recent issue of Earth and Planetary Science Letters, the distribution of biomarkers in 2.72-2.56 billion-year-old, Neoarchean rocks from the Hamersley Province on the Pilbara Craton in Western Australia. Their observations are consistent with a cyanobacterial source for 2-methylhopanes, in which cyanobacteria were likely the cornerstone of microbial communities in shallow-water ecosystems providing molecular oxygen, fixed carbon, and possibly fixed nitrogen.

Their data, revealing relative abundances of 3-methylhopanes, but not 2-methylhopanes, strongly correlate to stable carbon isotopic composition of insoluble particulate organic matter (kerogen). The unanticipated nature of this relationship provides evidence for a shallow-water locus of carbon cycling through aerobic oxidation of methane and, coincidentally, a means to demonstrate biomarker syngenicity.

Source: NAI Newsletter

Astrophysicists from the NAI's Carnegie Institution of Washington team and their colleagues have shown for the first time that a supernova could have triggered the solar system's formation under conditions of rapid heating and cooling. For several decades, scientists have thought that the solar system formed as a result of a shock wave from an exploding star--a supernova--that triggered the collapse of a dense, dusty gas cloud that contracted to form the sun and the planets. But detailed models of this formation process have only worked under the simplifying assumption that the temperatures during the violent events remained constant. The results, published in the October 20, 2008, issue of the Astrophysical Journal, have resolved this long-standing debate.

Source: NAI Newsletter