Pygsuia cells.

"Stealing" genes helps microbes to adapt

Scientists have identified how microbes can adapt their contents to different environments by “stealing” genes from other species.

The University of Exeter’s Dr Darren Soanes and Dr van der Giezen were part of an international collaboration involving researchers in Canada and the U.S.A. which has demonstrated the role of gene transfer – essentially “stealing” genes – in adapting mitochondria, the power source of the cells, to their environment.

In a recent issue of Current Biology, the authors examined the genetic sequence that codes for proteins in Pygsuia biforma, a single-celled microorganism which is distantly related to us, to examine their mitochondrion-related organelles (MROs).

Pygsuia cells live in sediment, a relatively oxygen-free environment, so their mitochondria do not depend on oxygen, as ours do – instead they have modified mitochondria called MROs; these organelles play a similar role, but use different fuel and different mechanisms to retrieve energy.

Lead author, Dalhousie University PhD student Courtney Stairs said of the project, “Understanding how genes are transferred between organisms is essential to understanding how organisms evolve and change over time. For instance, how do organisms, like Pygsuia, adapt to live without oxygen?”

“By integrating ‘stolen’ oxygen-independent pathways” (such as those used in conventional MROs) “into existing oxygen-dependent pathways,” the authors suggested.

Supporting this theory, the research uncovered that the Pygsuia MROs mix-and-match methods, enzymes and elements used in mitochondria and typical MROs, in addition to some novel functions – likely acquired by gene transfer - to make a structurally and biochemically unique MRO.

This work questions how organelles are currently classified, as it further confirms that not all organisms fit into the prototypical “mitochondrial” classification and shows the incredible flexibility of mitochondrial function, as well as the role of gene transfer, in developing new systems to extract energy from the environment.

“Finding examples of how the acquisition of a few genes can completely reinvent an organism's ability to survive in a new environment can be used by a bunch of fields of science - biological engineering, biotechology and medicine,” adds Stairs.

Date: 30 June 2014

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