by Cristen Teen

Electron micrographs of Bigelowiella natans. Credit: Paul Gilson

Electron micrographs of Bigelowiella natans. Credit: Paul Gilson

Scientists at Dalhousie University in Canada and the University of Melbourne have published a study in the journal Nature saying that hundreds of millions of years ago microscopic animals captured algae, held them captive, and repurposed their genes for energy production, allowing them to evolve into new and more powerful species.

This is some of the first hard evidence that quantum leaps in evolution occurred by one organism cannibalizing another, according to Professor Geoff McFadden, of the U. of M.’s School of Botany, who is part of the international research effort. These microscopic animals (In this instance, protozoa) used the stolen genes for photosynthesis, his team discovered.

In the study, researchers sequenced the genes of two specific algae, Guillardia theta and Bigelowiella natans, after realizing that their evolution was not complete. The algae cells had two nuclei, which is unusual because plant and animal cells only have one nucleus.

The results reveal a “missing link” in evolution, as the protozoa couldn’t completely hide all evidence of the captive algae, having been frozen in time and thus “caught in the act” by the genetic sequencing.

“We think that the genes for photosynthesis originally evolved only once about three billion years ago. So all plants, algae and blue green bacteria can produce their own energy from light because they have obtained these genes for photosynthesis,” Prof. McFadden said.

The captives lived inside the protozoan cell and, under the right conditions, the pair gradually became a single, unified organism – a process called endosymbiosis, literally living inside each other.