‘Extreme’ genes shed light on origins of photosynthesis

December 11, 2009

By Flinn Foundation

[Source: Bio-Medicine] – While most school children understand that green plants photosynthesize, absorb carbon dioxide and produce oxygen, few people consider the profound global-scale effects that photosynthesis has had on Earth. One of those actively shedding light on the origins and evolution of photosynthesis is Jeffrey Touchman, assistant professor in Arizona State University’s School of Life Sciences.

Oxygen, one of the by-products of photosynthesis by microbes such as cyanobacteria and their descendants (including algae and higher plants), transformed the Precambrian Earth and made possible the evolution of more complex organisms. With an $867,000 award from the National Science Foundation and the USDA National Institute of Food and Agriculture, Touchman works to illuminate large gaps in the available genetic data for photosynthetic microbes through the study of phototrophic extremophiles (organisms living in unusually harsh and exotic environments). His research is focused on genome sequencing and molecular analyses of heliobacteria, proteobacteria and a cyanobacterium with the ability to shift into anoxygenic (oxygen-free) photosynthesis in the presence of sulfide, a possible evolutionary “missing link” between anoxygenic and oxygenic photosynthetic organisms.

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