Evolution of life on Earth may hold key to finding life in outer space

08/12/05

Extremophiles explored by UH scientists showcased in 'Fantasy Worlds' planetarium exhibit

HOUSTON, Aug. 12, 2005 – Questions about the existence of life in outer space may have a surprisingly close-to-home answer, according to one University of Houston professor.

Understanding how life evolved on Earth is important in obtaining clues as to where else in the universe one might find life and what it might be like, said George E. Fox, a UH professor of biology and biochemistry. Fox is finishing work on a three-year research grant from NASA's Exobiology Program that seeks to understand life's origin.

In addition to his Earth-based research, Fox collaborated with the Houston Museum of Natural Science (HMNS) on a film project that explores the possibilities of life on other planets. Partially funded by an education and public outreach supplement to Fox's NASA grant, the joint production between HMNS and UH, called "Fantasy Worlds: Exploring the Limits of Life," is playing at the Burke Baker Planetarium at HMNS until December.

"Fantasy Worlds" explores extreme environments of Earth for a rare glimpse at microbes known as extremophiles that thrive in environments once thought too extreme to sustain life. Given the intense conditions under which these microbes are able to exist on Earth, the likelihood of finding life in outer space also increases. In "Fantasy Worlds," for each type of extremophile found, animators created a parallel imaginary alien planet on which these microbes are likely to thrive rather than just survive, allowing audiences to explore the types of alien worlds where scientists may one day find real alien life.

"All known living organisms on Earth share various biochemical properties, such as the same genetic code, the same major amino acids in proteins, and – with minor exceptions – the use of DNA or occasionally RNA as genetic material," Fox said. "This suggests life had a single origin from an earlier 'prebiotic' world, and research in NASA's Exobiology Program seeks to understand how this happened. The results of this type of research also help guide the search for life elsewhere in the universe, which is an important NASA objective."

The goal of Fox's grant – "The Origins of Translation and Early Evolution of Life" – is to understand when and how the ribosome (or cellular protein synthesis machinery) came into existence. Cellular protein synthesis is the process whereby RNA copies genetic information from DNA and translates it into proteins that are essential to the structure and function of all living cells and viruses and play a role in immune response. Fox and his group are examining the various components of the ribosome machinery trying to learn what parts came first and what was added later.

"Since many of the components of the ribosome are shared by all organisms, we know this machinery is very, very old," Fox said. "If we can discover the earliest aspects, then scientists may be able to devise experiments to see how simple RNAs might have given rise to this machinery. This information would help us to better understand how life evolved on Earth and how ribosomes actually work, which remains a fundamental problem in biochemistry."

One of only a small number of groups in the nation working on the history and evolution of the core ribosomal machinery, Fox and his team of scientists focus on comparing the sequences and 3-D shapes of biological molecules. Their research benefits greatly from the many ongoing genome sequencing projects.

"We do a lot of what is called bioinformatics, comparing molecules from different organisms," he said.

Fox's group recently received notification of two new NASA awards. One, from the Exobiology Program, will extend the work on translation to look for evidence of the RNA world preserved in extant genomes. The other, from NASA's Astrobiology Science and Technology Instrument Development Program, will conduct research to develop tests for the presence of living microorganisms that can be conducted robotically on other planetary bodies, including Mars.

Fox earned his bachelor's degree and his doctorate in chemical engineering from Syracuse University. Coming to UH in 1977, Fox has held numerous positions and, in addition to being a professor of biology and biochemistry in the College of Natural Sciences and Mathematics, he is an adjunct professor of chemical engineering in the Cullen College of Engineering. The author or co-author of more than 110 peer-reviewed publications, Fox has received numerous honors and awards for his research. He is an elected fellow of the American Academy of Microbiology, the American Association for the Advancement of Science and the American Institute of Medical and Biological Engineering. As a postdoctoral researcher with Carl Woese at the University of Illinois, Fox was involved in discovering the existence of a third kingdom of life now known as the Archaea. This discovery is regarded as one of the major breakthroughs in biology in the last 100 years.

A combined UH/NASA night with two free screenings of "Fantasy Worlds" for UH students, faculty and staff and NASA employees will be held 6 to 8 p.m., Tuesday, Aug. 23, at the museum. Otherwise, tickets for the show are $5 for adults, $3.50 for children (3-11) and seniors (62+) and $3 for Museum Members. For tickets information, visit www.hmns.org or call 713-639-4629.

Source: Eurekalert & others

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