James "Jim" P. Ferris was an American chemist. He is known for his contributions to the understanding of the origins of life on Earth, specifically by demonstrating a successful mechanism of clay-catalyzed polymerization of RNA, providing further evidence for the RNA World Hypothesis. Additionally, his work in atmospheric photochemistry has illuminated many of the chemical processes which occur in the atmospheres of Jupiter and Saturn's moon, Titan.
During more than fifty years of research, Ferris made landmark contributions to the field of prebiotic chemistry. His interests in the origins of life led him to explore in detail a diverse array of prebiotic reaction mechanisms, and to make the discovery of clay-directed RNA synthesis. By providing a plausible mechanism for the prebiotic synthesis of RNA oligomers, Ferris's method strengthened the RNA world hypothesis. In an effort to uncover the conditions of the early Earth's atmosphere and further establish the relationship between atmospheric processes and prebiotic chemistry, Ferris turned to observing Jupiter and Saturn's largest and most Earth-like moon, Titan.
Prebiotic synthesis
In the late 60s, Ferris published a set of collaborative studies with Leslie Orgel that elucidated several prebiotic pathways for the synthesis of biologically relevant macromolecules from hydrogen cyanide and cyano compounds. In another series of publications on chemical evolution, Ferris further expanded the understanding of these and other reactions, demonstrating, for example, mechanisms of hydrogen cyanide polymerization under a variety of conditions leading to purines, pyrimidines, amino acids, and a host of organic precursor molecules.
Montmorillonite catalysis and RNA polymerization
Ferris's work in prebiotic synthesis under early Earth conditions led him to investigate the use of the mineral montmorillonite as a surface for ribonucleotide polymerization and other processes. Montmorillonite is formed by the accumulation and breakdown of volcanic ash, and may have been present on the early Earth, making it a promising candidate for catalysis of prebiotic reactions. In early publications involving montmorillonite clays, Ferris demonstrated that, following adsorption of the nucleotides to its surface, the mineral can catalytically enhance the formation of polyadenine and polycytosine oligonucleotides and cyclic adenine monophosphates. The composition of montmorillonite clays can vary, and the presence of metal cations to stabilize the mineral's distinct negative charges were shown to affect binding and catalysis, as well. Later, Ferris was able to achieve catalysis of the phosphodiester bond between several activated ribonucleotides, resulting in RNA oligomers up to 50 nucleotides in length on the clay surface. In 2010, Ferris showed that montmorillonite is capable of affecting regioselectivity of the RNA oligomers it catalyzes. Starting with a mixture of D and L enantiomers of activated ribonucleotides, up to 76% of the resulting oligomers were homochiral, providing a new direction for the as-yet unanswered question of the origin of homochirality in modern biochemistry.
Photochemistry on other planets
Ferris constructed gaseous simulations of the atmospheres of Jupiter and Titan and analyzed their composition using a combination of photochemistry techniques, including x-ray photoelectron spectroscopy and infrared spectroscopy. Information gained from these studies could then be directly compared to measurements of their respective planets. The analysis of atmospheric processes on other planets in our solar system not only benefits the ongoing space exploration efforts of NASA, it may also hold insight into the history of our own planet, revealing atmospheric processes that would have been important to the emergence of life on a prebiotic Earth. By preparing analogs to Titan's atmospheric aerosols and irradiating the mixture of gases used, Ferris was able to probe refractive indices and observe synthesis reactions which could be used as models and compared directly to measurements of spectroscopy data recovered from NASA's Cassini-Huygens mission to Saturn.
Selected publications
Awards and recognition
Ferris received an NIH Career Award in 1969 which allowed him to greatly expand his research into prebiotic nucleotide synthesis. In 1996, he was awarded the Oparin Medal by ISSOL for his achievements and contributions to the field of origins of life chemistry. In 2012, the Rensselaer Polytechnic Institute established the James P. Ferris Fellowship in Astrobiology in his honor.