Double Membrane Prokaryotes: Astrobiology

Cyanobacteria

Cyanobacteria

NASA funded researcher James A. Lake, a Molecular Biologist from the University of California at Los Angeles’ Center for Astrobiology has discovered that early prokaryotes merged to create cyanobacteria.

By comparing proteins present in more than 3000 different prokaryotes – a type of single-celled organism without a nucleus — molecular biologist James A. Lake from the University of California at Los Angeles’ Center for Astrobiology showed that two major classes of relatively simple microbes fused together more than 2.5 billion years ago. Lake’s research reveals a new pathway for the evolution of life on Earth. These insights are published in the Aug. 20 online edition of the journal Nature.

The genetic machinery and structural organization of these two organisms merged to produce a new class of prokaryotes, called double membrane prokaryotes. As they evolved, members of this double membrane class, called cyanobacteria, became the primary oxygen-producers on the planet, generating enough oxygen to alter the chemical composition of the atmosphere and set the stage for the evolution of more complex organisms such as animals and plants.

“This work is a major advance in our understanding of how a group of organisms came to be that learned to harness the sun and then effected the greatest environmental change Earth has ever seen, in this case with beneficial results,” said Carl Pilcher, director of the NASA Astrobiology Institute at NASA’s Ames Research Center in Moffett Field, Calif., which co-funded the study with the National Science Foundation in Arlington, Va.

Below is the prokaryotic “tree” of life.

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